Escalation through Entanglement
Escalation through
Entanglement
How the Vulnerability of
Command-and-Control Systems Raises
the Risks of an Inadvertent Nuclear War
James M. Acton
IL 2018 NOI. Nuclear
Posture Review contains a highly consequential threat that has been largely
overlooked in the wave of commentary surrounding the document’s release:
the United States warns potential adversaries that it would consider using nu-
clear weapons in the event of “signiªcant nonnuclear strategic attacks . . . SU
NOI. or allied nuclear forces, their command and control, or warning and at-
tack assessment capabilities.”1 This threat was motivated by the growing vul-
nerability of these assets—in particular, the United States’ nuclear command,
controllo, communication, and intelligence (C3I or enabling) capabilities—to ad-
vanced nonnuclear weapons, and is presumably intended to deter attacks on
them.2 In issuing this threat, the Nuclear Posture Review illustrates that non-
nuclear attacks on nuclear forces and C3I capabilities could be highly
escalatory, even to the point of directly sparking a nuclear war.
A key challenge in managing these escalation risks is that attacks on an op-
ponent’s nuclear forces or their C3I capabilities (whether they belong to the
United States or another state) might not be deliberate. Since the late 2000s,
scholars have warned about the possibility of escalation in a U.S.-China con-
ºict resulting from so-called crisis instability generated by actual or threatened
NOI. nonnuclear operations that were intended to suppress China’s conven-
tional forces but inadvertently degraded its nuclear forces or associated C3I as-
sets located in the theater of operations, thus leading Beijing to fear it was
James M. Acton is co-director of the Nuclear Policy Program and holds the Jessica T. Matthews Chair at the
Carnegie Endowment for International Peace.
For insightful comments on previous drafts of this article, the author thanks Alexey Arbatov, Toby
Dalton, Catherine Dill, Geoffrey Forden, Michael Gerson, Charles Glaser, Ariel Levite, Jeffrey
Lewis, Li Bin, Austin Long, Tim Maurer, James Miller, George Perkovich, Pavel Podvig, Joshua
Pollack, Brad Roberts, Scott Sagan, Petr Topychkanov, Tong Zhao, and the anonymous reviewers,
as well as interviewees and participants at seminars where he presented this research. He is also
grateful to Jessica Margolis, William Ossoff, Thu-An Pham, Kathryn Taylor, Elizabeth Whitªeld,
and Lauryn Williams for research assistance. This work received generous ªnancial support from
the Carnegie Corporation of New York. The contents of this article are exclusively the author’s
responsibility.
1. NOI. Department of Defense, “Nuclear Posture Review” (Washington, D.C.: NOI. Department of
Defense, Febbraio 21, 2018), P. 21, https://media.defense.gov/2018/Feb/02/2001872886/-1/-1/
1/2018-NUCLEAR-POSTURE-REVIEW-FINAL-REPORT.PDF.
2. Ibid., P. 56.
International Security, Vol. 43, No. 1 (Estate 2018), pag. 56–99, doi:10.1162/ISEC_a_00320
© 2018 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.
Published under a Creative Commons Attribution 4.0 Unported (CC BY 4.0) licenza.
56
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Escalation through Entanglement 57
being disarmed.3 Similar, if more infrequent, scholarly warnings have been
voiced about a U.S.-Russia conºict.4 Such escalation would be inadvertent be-
cause it was the result of military operations or threats that were not intended
to be escalatory.5
This article’s thesis is that the risks of inadvertent escalation are even more
serious than these warnings suggest and are likely to increase signiªcantly
in futuro. Driving these risks is the possibility that Chinese, Russian, O
NOI. C3I assets located outside—potentially far outside—theaters of operation
could be attacked over the course of a conventional conºict. These assets
include satellites used for early warning, communication, and intelligence,
surveillance, and reconnaissance (ISR); ground-based radars and transmitters;
and communication aircraft.6 Such assets constitute key nodes in states’ nu-
3. Michael S. Chase, Andrew S. Erickson, and Christopher Yeaw, “Chinese Theater and Strategic
Missile Force Modernization and Its Implications for the United States,” Journal of Strategic Studies,
Vol. 32, No. 1 (Febbraio 2009), pag. 101–106, doi:10.1080/01402390802407434; Jeffrey G. Lewis,
“Chinese Nuclear Posture and Force Modernization,” Nonproliferation Review, Vol. 16, No. 2 (Luglio
2009), pag. 205–206, doi:10.1080/10736700902969661; Joshua Pollack, “Emerging Strategic Di-
lemmas in U.S.-Chinese Relations,” Bulletin of the Atomic Scientists, Vol. 65, No. 4 (July/August
2009), pag. 53–63, doi:10.2968/065004006; Tommaso J. Christensen, “The Meaning of the Nuclear
Evolution: China’s Strategic Modernization and U.S.-China Security Relations,” Journal of Strategic
Studi, Vol. 35, No. 4 (agosto 2012), pag. 467–471, doi:10.1080/01402390.2012.714710; Fiona S.
Cunningham and M. Taylor Fravel, “Assuring Assured Retaliation: China’s Nuclear Posture and
U.S.-China Strategic Stability,” International Security, Vol. 40, No. 2 (Autunno 2015), pag. 40–45, doi:10
.1162/ISEC_a_00215; Joshua H. Pollack, “Boost-Glide Weapons and U.S.-China Strategic Stability,"
Nonproliferation Review, Vol. 22, No. 2 (2015), pag. 157–161, doi:10.1080/10736700.2015.1119422;
Wu Riqiang, “Sino-U.S. Inadvertent Escalation” (Atlanta: Program on Strategic Stability Evalua-
zione, Georgia Institute of Technology, n.d.), https://www.yumpu.com/en/document/view/
38495325/wu-sino-us-inadvertent-escalation-program-on-strategic-stability-; Caitlin Talmadge,
“Would China Go Nuclear? Assessing the Risk of Chinese Nuclear Escalation in a Conventional
War with the United States,” International Security, Vol. 41, No. 4 (Primavera 2017), pag. 50–92,
doi:10.1162/ISEC_a_00274; and Tong Zhao and Li Bin, “The Underappreciated Risks of Entangle-
ment: A Chinese Perspective,” in James M. Acton, ed., “Entanglement: Russian and Chinese Per-
spectives on Non-Nuclear Weapons and Nuclear Risks” (Washington, D.C.: Carnegie Endowment
for International Peace, 2017), pag. 47–75, http://carnegieendowment.org/ªles/Entanglement
_interior_FNL.pdf. A much larger literature, with many contributions from foreign authors, ana-
lyzes nonnuclear threats to nuclear forces but does not connect them to inadvertent escalation.
4. James M. Acton, “Silver Bullet? Asking the Right Questions about Conventional Prompt
Global Strike” (Washington, D.C.: Carnegie Endowment for International Peace, 2013), pag. 120–
126, http://carnegieendowment.org/ªles/cpgs.pdf; and Alexey Arbatov, Vladimir Dvorkin, E
Petr Topychkanov, “Entanglement as a New Security Threat: A Russian Perspective,” in Acton, In-
tanglement, pag. 9–45.
5. Forrest E. Morgan et al., Dangerous Thresholds: Managing Escalation in the 21st Century (Santa
Monica, Calif.: RAND Corporation, 2008), pag. 23–25, http://www.rand.org/content/dam/rand/
pubs/monographs/2008/RAND_MG614.pdf. This concept was ªrst developed at length in Barry
R. Posen, Inadvertent Escalation: Conventional War and Nuclear Risks (Ithaca, N.Y.: Cornell University
Press, 1991), pag. 12–16.
6. Although threats to some of these assets have been discussed, their potential to spark inadver-
tent escalation has not.
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International Security 43:1 58
clear C3I systems, but they are also “entangled” with nonnuclear weapons in
two ways.7 First, they are typically dual use; questo è, they enable both nuclear
and nonnuclear operations. Secondo, they are increasingly vulnerable to non-
nuclear attack—much more vulnerable, Infatti, than most nuclear-weapon de-
livery systems.
Entanglement could lead to escalation because both sides in a U.S.-Chinese
or U.S.-Russian conºict could have strong incentives to attack the adversary’s
dual-use C3I capabilities to undermine its nonnuclear operations.8 As a result,
over the course of a conventional war, the nuclear C3I systems of one or both
of the belligerents could become severely degraded. È, Perciò, not just
NOI. nonnuclear strikes against China or Russia that could prove escalatory;
Chinese or Russian strikes against American C3I assets could also—a possibil-
ity that scholars have scarcely even considered since the end of the Cold War.9
Two escalation mechanisms that have not been previously discussed in the
academic literature are largely responsible for the increasing risk. Primo,
the target might interpret nonnuclear attacks against its dual-use C3I assets
that were motivated by conventional warªghting goals as preparations for nu-
clear use. It might respond to such “misinterpreted warning,” to coin a term,
by trying to deter the nuclear strike it believed might be coming or to mitigate
its potentially calamitous consequences. Such efforts, which might include
provocative nonnuclear operations to protect remaining C3I assets (ad esempio
strikes against anti-satellite weapons deep within the adversary’s territory) ac-
companied, perhaps, by nuclear threats, could prove highly escalatory. These
escalation pressures could arise even if the recipient of misinterpreted warning
were not concerned about the survivability of its nuclear forces—a key distinc-
tion from crisis instability.
7. To the best of the author’s knowledge, the ªrst use of the term “entangled” in this general sense
occurs in John D. Steinbruner, Principles of Global Security (Washington, D.C.: Brookings Institution
Press, 2000), P. 55.
8. Avery Goldstein, “First Things First: The Pressing Danger of Crisis Instability in U.S.-China Re-
lations,” International Security, Vol. 37, No. 4 (Primavera 2013), pag. 67–68, doi:10.1162/ISEC_a_00114;
and Stephen Biddle and Ivan Oelrich, “Future Warfare in the Western Paciªc: Chinese Antiaccess/
Area Denial, NOI. AirSea Battle, and Command of the Commons in East Asia,” International Secu-
rity, Vol. 41, No. 1 (Estate 2016), pag. 44–45, doi:10.1162/ISEC_a_00249.
9. There are passing references to this possibility in Arbatov, Dvorkin, and Topychkanov, “Entan-
glement as a New Security Threat,” p. 31; Zhao and Li, “The Underappreciated Risks of Entangle-
ment,” p. 51; and James N. Miller Jr. and Richard Fontaine, “A New Era in U.S.-Russian Strategic
Stability: How Changing Geopolitics and Emerging Technologies Are Reshaping Pathways to Cri-
sis and Conºict” (Cambridge, Mass. and Washington, D.C.: Belfer Center for Science and Interna-
tional Affairs, John F. Kennedy School of Government, Harvard University, and Center for
a New American Security, settembre 2017), P. 19, https://s3.amazonaws.com/ªles.cnas.org/
documents/CNASReport-ProjectPathways-Finalb.pdf?mtime(cid:2)20170918101504.
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Escalation through Entanglement 59
Secondo, a state with a damage-limitation doctrine would rely on sophisti-
cated C3I capabilities to locate and destroy its opponent’s nuclear forces and
conduct missile defense operations. If these dual-use enabling capabilities
were subject to attack in a conventional conºict—or even if their possessor
feared they might be—the state could worry that its window of opportunity
for conducting effective damage-limitation operations might have closed
by the time the war turned nuclear. In questo caso, the state might take escalatory
measures to protect its C3I system or even initiate counterforce operations pre-
emptively. This escalation mechanism, which might be termed the “damage-
limitation window,” is distinct from crisis instability because it is driven by the
state’s desire to hold an opponent’s nuclear forces at risk, not to protect its
own. It is distinct from misinterpreted warning because it could operate even
if the state did not believe that nuclear use by an adversary might be immi-
nent; the state would only have to believe that such escalation was possible
later on.
An additional implication of C3I entanglement is that the risks of crisis
instability are more serious than portrayed in the academic literature. Schol-
arly warnings about crisis instability have focused on the potential for U.S.
nonnuclear operations to degrade Chinese nuclear forces, but have also
identiªed the risk of inadvertent threats to China’s nuclear C3I capabilities
located in the theater of operations.10 These threats have received particular
attention since the United States acknowledged, In 2013, that it seeks to defeat
potential adversaries’ antiaccess/area-denial capabilities by holding relevant
C3I assets at risk as part of the concept formerly known as AirSea Battle
(which was renamed, In 2015, as the Joint Concept for Access and Maneuver in
the Global Commons and has since been further developed).11 If overlap exists
between the communication systems for China’s land-based nuclear and non-
nuclear missiles, as some analysts have suggested, China could mistake U.S.
strikes designed to disable its nonnuclear missiles as an attack against its nu-
clear forces.12
10. Talmadge, “Would China Go Nuclear?” pp. 78–79, 83.
11. Air-Sea Battle Ofªce, “Air-Sea Battle: Service Collaboration to Address Anti-Access and Area
Denial Challenges” (Washington, D.C.: NOI. Department of Defense, May 2013), P. 7, http://
archive.defense.gov/pubs/ASB-ConceptImplementation-Summary-May-2013.pdf.
12. Christensen, “The Meaning of the Nuclear Evolution,” p. 468. For a slightly dated description
of Chinese command and control that implies an overlap, see John Wilson Lewis and Xue Litai,
Imagined Enemies: China Prepares for Uncertain War (Stanford, Calif.: Stanford University Press,
2006), pag. 197–201. For opposing views, see Cunningham and Fravel, “Assuring Assured Retalia-
zione,” pp. 42–45; and Michael Glosny, Christopher Twomey, and Ryan Jacobs, “U.S.-China Strate-
gic Dialogue, Phase VIII Report” (Monterey, Calif.: Center on Contemporary Conºict, Naval
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International Security 43:1 60
Entanglement, Tuttavia, has created other potential triggers for crisis insta-
bility. The United States, Per esempio, has—or could develop—incentives to
launch nonnuclear kinetic attacks against existing and probable future dual-
use Chinese or Russian early-warning capabilities, including over-the-horizon
radars, ballistic missile early-warning radars (BMEWRs), and early-warning
satellites, that are located outside the theater of operations.13 (Kinetic weapons,
which often use explosive warheads, aim to damage or destroy targets
by transferring kinetic energy to them through physical contact; non-
kinetic weapons include directed energy and cyber capabilities.) Inoltre,
Russian strikes on the United States could precipitate crisis instability if
NOI. communication aircraft (currently, the United States’ most survivable
means to communicate with its nuclear forces) become vulnerable.
Entanglement could catalyze escalation in any major U.S.-Chinese or U.S.-
Russian conventional conºict, irrespective of its origins. That said, for the sake
of concreteness, the kind of U.S.-Chinese conºict that forms the backdrop to
this article would most likely begin with a Chinese attempt to reunify with
Taiwan by force (either unprovoked or because the government of Taiwan had
declared independence), followed by U.S. intervention on behalf of Taiwan.
The most probable cause of a major U.S.-Russian conºict would be the inva-
sion and occupation of one or more of the Baltic states by Russia, followed by a
U.S.-led counterattack to liberate them. In entrambi i casi, ªghting could spread
from the theater in which it started.
There would, Ovviamente, be important differences between the escalation dy-
namics in a U.S.-Chinese and U.S.-Russian conºict. Nevertheless, there would
also be important similarities that help illustrate the general nature of the risks
stemming from entanglement. In particular, entanglement could not only pre-
cipitate the use of nuclear weapons directly, but could also frustrate efforts to
manage nonnuclear escalation, thus raising the risk of nuclear use later on.
Early in a conºict, Per esempio, to emphasize its limited war aims, the United
States might refrain from conducting nonnuclear strikes beyond a certain dis-
tance into an adversary’s territory. Subsequently, if the United States became
worried that key C3I satellites were at risk, it might believe that it had to
Postgraduate School, novembre 2014), P. 10, http://calhoun.nps.edu/bitstream/handle/10945/
44733/2014%20008%20-%20US-China%20Phase%20VIII%20Report.pdf.
13. There are passing references to this possibility in Arbatov, Dvorkin, and Topychkanov, “Entan-
glement as a New Security Threat.” Over-the-horizon radars are brieºy mentioned in Christopher
P. Twomey, “Asia’s Complex Strategic Environment: Nuclear Multipolarity and Other Dangers,"
Asia Policy, Gennaio 2011, P. 64.
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Escalation through Entanglement 61
attack Chinese or Russian anti-satellite (ASAT) weapons located further
beyond the border.
the damage-limitation window,
This article begins by outlining the technological and doctrinal develop-
ments that are increasing entanglement. It then lays out three mechanisms—
misinterpreted warning,
and crisis
instability—by which entanglement might spark escalation and identiªes the
conditions under which escalation would be most likely. To provide a con-
crete demonstration of the severity of the escalation risks, the article then de-
scribes the likely effectiveness and effects of nonnuclear kinetic attacks against
the U.S. early-warning system. It also considers the risks of cyber interference
with dual-use Chinese, Russian, and U.S. early-warning assets, and in particu-
lar, the danger of the target’s misinterpreting cyber espionage as an attempt to
disable or destroy those assets.
With risk reduction likely to prove difªcult, unilateral restraint and actions
represent the most feasible policy responses for the short term. Although such
steps would likely be only moderately effective in themselves, they could help
pave the way for cooperative efforts in the future. Although difªcult to orches-
trate, cooperative risk-reduction would be desirable because, as this article em-
phasizes in the conclusion, the risks created by entanglement are likely to
grow in the future, absent action to mitigate them.
The Technological and Doctrinal Drivers of Entanglement
Entanglement describes interactions between the nuclear and nonnuclear
domini. For current purposes, its most important manifestations are the dual-
use nature of many C3I assets as well as nonnuclear threats (real or perceived)
to nuclear forces or their C3I infrastructure. Other manifestations, mentioned
only in passing here, are dual-use delivery systems; nuclear delivery systems
that are superªcially similar to nonnuclear ones; and the colocation of nu-
clear and nonnuclear delivery systems or C3I assets. Since the end of the
Cold War, entanglement has increased signiªcantly—and,
is still
increasing—as the result of four trends in military technology and doctrine.
Infatti,
growing technological threats
Primo, profound changes in weaponry have signiªcantly magniªed nonnuclear
threats to states’ C3I assets and, to a lesser extent, their nuclear forces. These
changes include the deployment of two entirely new classes of weapons:
cyberweapons (which could threaten both C3I capabilities and nuclear forces)
and nonnuclear strategic ballistic missile defense systems (which could inter-
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International Security 43:1 62
cept nuclear weapons after launch). The effectiveness of existing types of
nonnuclear weapons has also improved dramatically. Per esempio, although
both the United States and the Soviet Union had some capability to target sat-
ellites without nuclear weapons by the end of the Cold War, nonnuclear ASAT
weapons—both kinetic and non-kinetic—pose a much more potent threat to-
day.14 High-precision conventional weapons have also improved signiªcantly,
including with the introduction of satellite-guided munitions. Over the next
couple of decades, further substantial improvements can be expected in all of
these weapon types, and entirely new types of nonnuclear weapons, including
long-range hypersonic weapons, may be deployed.15
growing vulnerability of c3i capabilities
Secondo, changes in enabling technologies have exacerbated the growing vul-
nerability of the C3I assets involved in nuclear operations (whether these as-
sets are dual use or not). Digital networks have become ubiquitous, for
esempio, creating the possibility of cyber interference. Inoltre, the United
States, at least in an effort to reduce costs, has pursued greater commonality in
the enabling systems, such as the receivers for satellite signals, associated with
different nuclear-weapon delivery systems.16 This development, Tuttavia,
could magnify cyber risks. If, Per esempio, there was a design ºaw in a com-
mon receiver that left it vulnerable to being disabled by a cyberattack, then all
the nuclear-weapon delivery systems that used the receiver could be simulta-
neously compromised.
Another cause of this growing vulnerability—at least for the U.S. nuclear
C3I system—is a reduction in redundancy (there is insufªcient publicly avail-
able information to assess how the redundancy of the Chinese and Russian
systems has changed).17 In the late 1980s and early 1990s, Per esempio, two
largely independent satellite-based communication systems were in use for
transmitting orders for the employment of U.S. nuclear weapons.18 The
14. Laura Grego, “A History of Anti-Satellite Programs” (Cambridge, Massa.: Union of Concerned
Scientists, Gennaio 2012), http://www.ucsusa.org/sites/default/ªles/legacy/assets/documents/
nwgs/a-history-of-ASAT-programs_lo-res.pdf.
15. Acton, “Silver Bullet?"
16. Department of the Air Force, NOI. Department of Defense, “Department of Defense Fiscal Year
(FY) 2017 President’s Budget Submission: Other Procurement, Air Force” (Washington, D.C.: NOI.
Department of Defense, Febbraio 2016), P. 267, line item 834210, http://www.saffm.hq.af.mil/
Portals/84/documents/FY17/AFD-160208-049.pdf?ver(cid:2)2016-08-24-102038-590.
17. For an overview of the late 1980s system, see Peter Vincent Pry, The Strategic Nuclear Balance,
Vol. 2: Nuclear Wars: Exchanges and Outcomes (New York: Crane Russak, 1990), pag. 18–22.
18. Curtis Peebles, High Frontier: The U.S. Air Force and the Military Space Program (Washington,
D.C.: Air Force History and Museums Program, 1997), pag. 44–54, http://www.dtic.mil/dtic/tr/
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Escalation through Entanglement 63
Defense Satellite Communications System served intercontinental ballistic
missiles (ICBMs). A separate system, the Air Force Satellite Communications
System (AFSATCOM), served ICBMs, sea-launched ballistic missiles (SLBMs),
and nuclear-armed aircraft, and consisted of special transponders hosted on
tens of satellites mostly used for other purposes.19 Today, the United States is
in the process of deploying just four Advanced Extremely High Frequency
(AEHF) satellites that will be the nation’s sole space-based system for trans-
mitting nuclear employment orders once legacy Milstar satellites have been re-
tired. Allo stesso modo, at the end of the Cold War, the United States operated two
independent networks of radio antennae to communicate with submarines.20
One of these networks, which could provide global coverage using two ex-
tremely low-frequency antennae in the continental United States, has since
been shut down.21 Although modernization of the remaining assets would
presumably enable them to function more effectively in the extraordinarily
stressful conditions of a nuclear war, the overall loss of redundancy—a conse-
quence of budgetary pressures—appears to have left the U.S. nuclear C3I sys-
tem less resilient against nonnuclear attack.
growing reliance on dual-use c3i assets
Third, the U.S. nuclear C3I system has always used some dual-use assets, E
is becoming increasingly reliant on them, raising the likelihood of its being at-
tacked in a nonnuclear conºict. The United States has, Per esempio, never
ªelded communication satellites that were used exclusively for nuclear opera-
tions.22 Today, Milstar and AEHF satellites represent the United States’ most
secure space-based means of communicating with both nuclear and “high-
priority” nonnuclear users (users tasked with particularly important or time-
critical missions).23 Infatti, the vast majority of data transmitted by these
fulltext/u2/a442844.pdf. The systems were not entirely independent, because some transponders
belonging to the Air Force Satellite Communications System were hosted by Defense Satellite
Communications System satellites.
19. UN 1981 estimate suggested that as many as thirty AFSATCOM transponders could be de-
ployed by 1990. See Mark Hewish, “Satellites Show Their Warlike Face,” New Scientist, ottobre 1,
1981, P. 39.
20. NOI. Department of the Navy, “Submarine Communications Master Plan” (Washington, D.C.:
NOI. Department of the Navy, Dicembre 1995), appendix B, http://fas.org/man/dod-101/navy/
docs/scmp/part07.htm.
21. Robert Imrie, “Navy to Shut Down Sub Radio Transmitters,” Associated Press, settembre 26,
2004, http://usatoday30.usatoday.com/tech/news/2004-09-26-sub-radio-offair_x.htm.
22. Peebles, High Frontier, pag. 44–52.
23. Air Force Space Command, “Advanced Extremely High Frequency System” (Washington,
D.C.: NOI. Air Force, Marzo 22, 2017), http://www.afspc.af.mil/About-Us/Fact-Sheets/Display/
Article/249024/advanced-extremely-high-frequency-system/.
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International Security 43:1 64
satellites is almost certainly associated with nonnuclear operations. Because it
could be difªcult for an adversary to disrupt the operation of these satellites in
non-destructive ways (jamming, Per esempio), they could become targets of di-
rect attack in a conventional conºict.
Starting in the last decade of the Cold War, the United States has increased
reliance on dual-use systems by assigning nonnuclear roles to C3I assets that
used to be employed solely for nuclear operations. Until the mid-1980s, for ex-
ample, NOI. early-warning satellites were used exclusively for detecting the
launch of nuclear-armed missiles.24 Today, they enable a variety of nonnuclear
missions by, Per esempio, providing cuing information for missile defenses in-
volved in intercepting conventional ballistic missiles.25
In a parallel series of developments, the United States has dismantled vari-
ous land-based nuclear-only communication capabilities. Per esempio, IL
Emergency Rocket Communications System, which could transmit em-
ployment orders from modiªed ICBMs launched to overºy missile ªelds in
the United States, was taken ofºine in the 1990s.26 A decade or so later, IL
Survivable Low Frequency Communications System, which allowed ICBMs to
receive launch orders from radio antennae, was also scrapped.27
The net effect of these developments is that, today, most assets in the U.S.
nuclear C3I system “support both nuclear and conventional missions,” accord-
ing to the U.S. Government Accountability Ofªce.28 In fact, every C3I asset
listed in the 2018 Nuclear Posture Review is known to be dual use, except
for nuclear-weapon control capabilities directly associated with delivery
systems (and perhaps also the United States’ system for detecting nuclear
24. Their adoption for nonnuclear missions is discussed in Norman Friedman, Seapower and Space:
From the Dawn of the Missile Age to Net-Centric Warfare (Annapolis: Naval Institute Press, 2000),
pag. 242–245.
25. Committee on an Assessment of Concepts and Systems for U.S. Boost-Phase Missile Defense
in Comparison to Other Alternatives and Division on Engineering and Physical Science of the Na-
tional Research Council, Making Sense of Ballistic Missile Defense: An Assessment of Concepts and Sys-
tems for U.S. Boost-Phase Missile Defense in Comparison to Other Alternatives (Washington, D.C.:
National Academies Press, 2012), P. 116, https://www.nap.edu/catalog/13189/making-sense-of-
ballistic-missile-defense-an-assessment-of-concepts.
26. Federation of American Scientists, “Emergency Rocket Communications System (ERCS)"
(Washington, D.C.: Federation of American Scientists, April 27, 1998), http://fas.org/nuke/guide/
usa/c3i/ercs.htm.
27. Carla Williams, “Minot Completes Minuteman Emergency Communications Upgrade” (Wash-
ington, D.C.: NOI. Air Force, novembre 17, 2005), http://www.af.mil/News/ArticleDisplay/tabid/
223/Article/132716/minot-completes-minuteman-emergency-communications-upgrade.aspx.
28. Christina Chaplain, “Nuclear Command, Control, and Communications: Update on DOD’s
Modernizzazione,” GAO-15-584R (Washington, D.C.: NOI. Government Accountability Ofªce,
Giugno 15, 2015), P. 1, http://www.gao.gov/assets/680/670801.pdf.
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Escalation through Entanglement 65
explosions—though some of its detectors are hosted by Global Positioning
System satellites).29
The Russian nuclear C3I system probably also includes some dual-use as-
sets. In a 2007 edition of the journal Military Thought, published by the Russian
ministry of defense, one retired and one serving military ofªcer describe how
satellites then under development would be used for communicating with
“strategic and nonstrategic nuclear forces,” as well as nonnuclear forces and
even “federal and regional government agencies.”30 Their description appears
to refer to communication satellites that have since been deployed as part of
Russia’s Uniªed Satellite Communication System. Separately, secondo
state-controlled Russian media outlets, Moscow has recently acquired a num-
ber of airborne command posts capable of communicating with both nuclear
and conventional forces.31 Moreover, as discussed below, various types of
Russian radars are already dual use, and Russia’s new early-warning satellites
could take on nonnuclear missions in the future.
The extent of the overlap between the communication systems for China’s
land-based nuclear and conventional missiles has been the subject of consider-
able debate among analysts.32 Beijing’s recent deployment of the DF-26 ballis-
tic missile provides some additional evidence that this overlap is signiªcant.
The warhead (or warheads) on an individual missile body can, according to an
apparently authoritative Chinese source, be rapidly switched between nuclear
and conventional variants.33 This capability suggests that the physical commu-
nication infrastructure associated with these missiles can be used to transmit
nuclear and nonnuclear employment orders. This evidence is not deªnitive,
Tuttavia, because it is possible that missiles are transferred between nuclear
and conventional missile brigades when the warhead type is changed (Anche se
this procedure would seem to obviate the whole purpose of the “change the
29. NOI. Department of Defense, “Nuclear Posture Review,” pp. 56–57.
30. V.A. Grigoryev and I.A. Khvorov, “Military Satellite Communications Systems: Current State
and Development Prospects,” Military Thought, Vol. 16, Nos. 3–4 (Luglio 1, 2007), P. 149; see also
P. 150.
31. “Russian Next-Generation ‘Doomsday Plane’ Finally Ready for Action,” Sputnik, Luglio 28,
2016, http://sputniknews.com/russia/20160728/1043728673/russia-doomsday-plane-ready.html.
32. Christensen, “The Meaning of the Nuclear Evolution,” p. 468; Lewis and Xue, Imagined En-
emies, pag. 197–201; Cunningham and Fravel, “Assuring Assured Retaliation,” pp. 42–45; E
Glosny, Twomey, and Jacobs, “U.S.-China Strategic Dialogue, Phase VIII Report,” p. 10.
‘Why We Had to De-
33. Andrew S. Erickson, “Academy of Military Science Researchers:
velop the Dongfeng-26 Ballistic Missile’—Bilingual Text, Analysis, and Related Links,"
andrewerickson.com, Dicembre 5, 2015, http://www.andrewerickson.com/2015/12/academy-of-
military-science-researchers-why-we-had-to-develop-the-dongfeng-26-ballistic-missile-bilingual-
text-analysis-links/.
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International Security 43:1 66
warhead, not the missile” capability).34 Additionally, as discussed below, vari-
ous Chinese early-warning capabilities are already, or may become, dual use.
growing doctrinal threats
Fourth, the military doctrines of China, Russia, and the United States appear to
envision attacks on space- and land-based C3I assets, including dual-use ones,
to further conventional warªghting goals. In the case of the United States, Questo
tactic was explicitly articulated in the AirSea Battle concept. Nel frattempo,
Washington has openly expressed concern that both China and Russia seek to
hold U.S. C3I satellites at risk to support potential efforts to undermine U.S.
conventional operations.35 The U.S. intelligence community has highlighted
the threat from both states to U.S. early-warning satellites, in particular.36 A
consistent picture is painted by Chinese and Russian sources. Per esempio, IL
Science of Second Artillery Campaigns, a classiªed but leaked textbook from 2004
believed to contain an authoritative description of China’s strategic doctrine,
appears to endorse attacks against U.S. early-warning radars as a way of sup-
pressing missile defenses in a conventional conºict.37 Moreover, Chinese ex-
perts have openly advocated for the ability to attack U.S. early-warning
satellites.38 In a similar vein, Russian experts have stated that, in a conven-
tional conºict, Moscow would consider attacking U.S. C3I assets, including
ground-based early-warning radars.39
34. Jordan Wilson, “China’s Expanding Ability to Conduct Conventional Missile Strikes on
Guam” (Washington, D.C.: U.S.-China Economic and Security Review Commission, May 10,
2016), P. 8, https://www.uscc.gov/sites/default/ªles/Research/Staff%20Report_China%27s%20
Expanding%20Ability%20to%20Conduct%20Conventional%20Missile%20Strikes%20on%20Guam
.pdf.
35. Defense Intelligence Agency, “Russia Military Power: Building a Military to Support Great
Power Aspirations,” DIA-11-1207-161 (Washington, D.C.: Defense Intelligence Agency, 2017),
P. 36, http://www.dia.mil/Portals/27/Documents/News/Military%20Power%20Publications/
Russia%20Military%20Power%20Report%202017.pdf; and Ofªce of the Secretary of Defense, “Mil-
itary and Security Developments Involving the People’s Republic of China 2017,” annual report to
Congress (Washington, D.C.: NOI. Department of Defense, 2017), P. 35, https://www.defense.gov/
Portals/1/Documents/pubs/2017_China_Military_Power_Report.PDF?ver(cid:2)2017-06-06-141328-
770.
36. Daniel R. Coates, “Worldwide Threat Assessment of the U.S. Intelligence Community,” state-
ment for the record (Washington, D.C.: Ofªce of the Director of National Intelligence, Marzo 6,
2018), P. 13, https://www.dni.gov/ªles/documents/Newsroom/Testimonies/Final-2018-ATA—
Unclassiªed—SASC.pdf.
37. Second Artillery Corps, People’s Liberation Army, The Science of Second Artillery Campaigns,
unclassiªed U.S. government translation (Beijing: PLA Press, 2004), pag. 397–398. Given that this
section discusses suppressing both missile and air defenses, this reference is probably to both mis-
sile and aircraft early-warning radars.
38. Zhao and Li, “The Underappreciated Risks of Entanglement,” p. 51; and Chase, Erickson, E
Yeaw, “Chinese Theater and Strategic Missile Force Modernization and Its Implications for the
stati Uniti,” p. 83.
39. Arbatov, Dvorkin, and Topychkanov, “Entanglement as a New Security Threat,” p. 31.
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Escalation through Entanglement 67
Escalation Pathways: Effects of Entanglement on Conºict Dynamics
One consequence of growing entanglement is the possibility of “incidental
attacks” on an opponent’s nuclear forces or their enabling capabilities. In
such an attack, one state strikes an adversary’s dual-use assets to inºuence
the outcome of a conventional conºict but, in the process, inadvertently
degrades its nuclear capabilities.40 Strikes against dual-use C3I capabilities—
communication and early-warning assets, in particular—would probably rep-
resent the most consequential type of incidental attack. Incidental attacks
could also result, Tuttavia, from strikes against dual-use weapon delivery
platforms, such as aircraft and missiles.
Incidental attacks have the potential to be escalatory, in no small part be-
cause it could be effectively impossible for the target to distinguish them from
deliberate attacks intended to undermine its ability to conduct nuclear opera-
zioni (including obtaining warning of an incoming nuclear strike). The general
difªculty of assessing intent would likely be compounded by the fog of war,
which would probably be thick in any major conventional conºict and further
exacerbated by likely attacks against ISR capabilities. Inoltre, as Barry
Posen argued, a variant of the security dilemma might arise: prudence could
require a state to treat attacks on its nuclear forces or their enabling capabilities
as deliberate and take actions to protect them; to assume that surviving assets
were not threatened would carry the risk that they might be destroyed if the
enemy’s intent had been misjudged.41
There are three distinct pathways—misinterpreted warning, the damage-
limitation window, and crisis instability—through which actual or threatened
incidental attacks could spark inadvertent escalation.
misinterpreted warning
In a conventional war between two nuclear-armed states, nonnuclear attacks
against an opponent’s dual-use enabling capabilities motivated by conven-
tional warªghting goals could be indistinguishable from operations intended
to prepare the battlespace for nuclear use. Such attacks, Perciò, could create
misinterpreted warning—especially if the state launching them was in danger
of losing the war.
Although a state concerned about becoming the target of a nuclear attack
might not use nuclear weapons immediately, its concern might lead it to act in
ways that could catalyze further escalation, raising the likelihood of nuclear
40. This deªnition is somewhat different from the one in Posen, Inadvertent Escalation, P. 2.
41. Ibid., pag. 12–16.
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International Security 43:1 68
use later on. The state would be motivated by a desire to avoid or mitigate the
potentially catastrophic costs of becoming the target of even a limited nuclear
strike; in contrast to crisis instability, these escalation pressures could be felt
even if the state was not concerned about its nuclear forces being vulnerable or
its ability to transmit employment orders to them.
Two questions arise when assessing the escalation risks of misinterpreted
warning. Primo, how likely is it that the target would interpret nonnuclear
strikes against its dual-use C3I assets as possible preparations for nuclear use?
Secondo, if the target did become concerned that it might shortly be on the re-
ceiving end a nuclear strike, would it be likely to react in ways that tended to
catalyze further escalation?
Because Moscow and Beijing have different nuclear postures and doctrines,
there are somewhat different reasons why their striking dual-use U.S. enabling
assets might generate misinterpreted warning. NOI. incidental strikes on dual-
use Chinese or Russian C3I assets could also lead to misinterpreted warning,
though this possibility is not discussed further here.
how misinterpreted warning could occur. The United States govern-
ment has indicated its belief that, in a conventional conºict, Russia might opt
for limited nuclear use in an attempt to compel the United States into backing
down—a strategy sometimes termed “escalate to de-escalate” in the Western
discourse.42 It also appears to worry that, if a limited nuclear war escalated,
Russia might launch large-scale damage-limitation strikes against U.S. nuclear
forces (even though such strikes could not deprive the United States of a
second-strike capability today).43 Whether these beliefs accurately reºect
Russian strategy is essentially immaterial for current purposes; Piuttosto, they are
important because, right or wrong, they would likely inform the United States’
assessment of Russia’s intentions in a conºict. In this way, for at least three rea-
sons, these beliefs create the potential for Washington to misinterpret Russian
incidental strikes against dual-use U.S. C3I assets as preparations for nu-
clear use.
Primo, Russia might attack ground-based or space-based U.S. early-warning
assets to defeat European missile defenses that were proving effective in inter-
42. NOI. Department of Defense, “Nuclear Posture Review,” p. 30; and Robert Work and
James Winnefeld, prepared statement, Nuclear Deterrence in the 21st Century, hearing before the
Committee on Armed Services, NOI. House of Representatives, 114th Cong., 1st sess., Giugno 25,
2015, P. 4, http://docs.house.gov/meetings/AS/AS00/20150625/103669/HHRG-114-AS00-Wstate-
WinnefeldJrUSNJ-20150625.pdf.
43. The emphasis that the United States places on force survivability in ofªcial policy can only be
explained by concerns about damage-limiting Russian strikes.
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Escalation through Entanglement 69
cepting its nonnuclear missiles. Washington might see such attacks, Tuttavia,
as preparations to ensure that limited nuclear strikes by Russia could penetrate
the United States’ homeland missile defenses. Government-afªliated Russian
experts have publicly advocated “limited strategic strikes” against the U.S.
homeland under a variety of circumstances (including if Russia became con-
cerned that the United States was about to embark on a conventional counter-
force campaign against its nuclear forces).44 Such experts have also expressed
concern that U.S. missile defenses might be capable of defeating such strikes.
Infatti, the United States has declared that homeland defenses “would be em-
ployed to defend the United States against limited missile launches from any
source” (even if such defenses cannot cope with large-scale attacks).45 In
risposta, Russian strategists have suggested that, prior to launching limited
strategic strikes, Moscow should try to neutralize those defenses by attacking
the U.S. early-warning system.46 If Washington interpreted strikes against its
early-warning capabilities in this light, misinterpreted warning could arise.
Secondo, Russia could attack dual-use U.S. communication assets to under-
mine a variety of American nonnuclear operations. Washington could inter-
pret such attacks, Tuttavia, as an attempt to forestall a proportionate U.S.
response to the limited use of low-yield nuclear weapons. Nuclear-armed air-
craft might well be the United States’ preferred means of responding to a lim-
ited nuclear strike, because the B-61 gravity bomb has the lowest-yield nuclear
option in the U.S. arsenal.47 The communication links for deployed aircraft,
Tuttavia, are particularly vulnerable to being severed.48 Russian incidental
strikes might destroy the satellites and ground-based transmitters that could
enable communications with aircraft operating over or around Russia. Mean-
while, communication aircraft operating over the United States would proba-
bly be too distant to direct operations in that region. Washington, Perciò,
could interpret Russian attacks against U.S. communication links as an at-
tempt to deny the United States the ability to respond in kind to a low-yield
44. Arbatov, Dvorkin, and Topychkanov, “Entanglement as a New Security Threat,” pp. 20–21.
45. NOI. Department of Defense, “Ballistic Missile Defense Review Report” (Washington, D.C.:
NOI. Department of Defense, Febbraio 2010), P. 13, http://archive.defense.gov/bmdr/docs/
BMDR%20as%20of%2026JAN10%200630_for%20web.pdf.
46. Arbatov, Dvorkin, and Topychkanov, “Entanglement as a New Security Threat,” p. 31.
47. IL 2018 Nuclear Posture Review calls for the acquisition of additional submarine-based low-
yield nuclear capabilities. Whether and when these weapons will be deployed remains to be seen.
See U.S. Department of Defense, “Nuclear Posture Review,” pp. 54–55.
48. In theory, the United States could still use aircraft for nuclear operations by “pre-program-
ming” targets at take-off or shortly afterward. This approach, Tuttavia, would undermine the
maintenance of positive control throughout a ºight, which is a key rationale for maintaining nu-
clear-armed aircraft.
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International Security 43:1 70
nuclear strike in the hope that it would be deterred from a more forceful re-
sponse by the fear of further escalation.
Third, Russian attacks against dual-use U.S. early-warning or communica-
tion assets would risk being seen as a signal of Russia’s resolve to use nuclear
weapons unless the United States conceded to its demands. In an effort to de-
ter limited nuclear use by Russia, senior U.S. ofªcials have publicly stressed
the risk of escalation to a strategic nuclear war, stating, Per esempio, that “any-
one who thinks they can control escalation through the use of nuclear weapons
is literally playing with ªre.”49 Because Russian incidental strikes against dual-
use U.S. C3I assets could help Russia ªght a strategic nuclear war, they could
be interpreted by Washington as an effort to enhance the credibility of limited
nuclear use. Per esempio, degrading the U.S. early-warning system might pre-
vent the United States from launching ICBMs, dispersing bombers, or shelter-
leaders before they were eliminated in a nuclear attack.
ing national
Allo stesso modo, disabling communication systems might slow a U.S. nuclear re-
sponse to a Russian counterforce strike, giving Russia time for follow-up
damage-limitation strikes.
To be sure, the United States’ interpretation of Russian strikes against dual-
use U.S. enabling assets would likely depend on the context. Had Russia
raised the alert level of its nuclear forces, dispersed them, or even issued or-
ders to prepare them for nuclear employment? Had Moscow put into action
plans to try to ensure the continuity of government in the event of a nuclear
war? What messages was the government sending to its own population?
Would it be threatened from within if it lost the war? In practice, such ques-
tions could be extremely difªcult to answer because, by the time that Russia
had attacked dual-use U.S. early-warning and communication assets, it would
probably have launched extensive attacks against U.S. ISR capabilities, poten-
tially denying much needed contextual information to the United States.50 In
the absence of this information, Washington might feel its most prudent course
of action was to assume the worst about Moscow’s intentions.
The risk of the United States’ misinterpreting Chinese nonnuclear strikes
against dual-use U.S. C3I assets as preparations for nuclear use would proba-
bly be lower than in the case of Russia for two reasons. Primo, in contrast to
Moscow, Beijing has adopted a no-ªrst-use pledge. Secondo, unlike their
49. Work and Winnefeld, prepared statement, P. 4. See also U.S. Department of Defense, “Nuclear
Posture Review,” p. 30.
50. Forrest E. Morgan, “Deterrence and First-Strike Stability in Space: A Preliminary Assessment”
(Santa Monica, Calif.: RAND Corporation, 2010), P. 19, http://www.rand.org/content/dam/
rand/pubs/monographs/2010/RAND_MG916.pdf.
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Escalation through Entanglement 71
Russian counterparts, Chinese leaders can have absolutely no doubt that nu-
clear ªrst use would do nothing to meaningfully limit the damage their
country would suffer in a nuclear war with the United States. Di conseguenza,
Washington would be unlikely to interpret Chinese nonnuclear strikes as prep-
arations to ªght and win a strategic nuclear war.
That said, the United States could still interpret Chinese attacks against its
early-warning system as preparations for limited nuclear strikes intended to
terrify the United States into terminating a conºict on terms not too unfavor-
able to Beijing. Fairly or not, Washington does not have complete conªdence in
the reliability of China’s no-ªrst-use pledge.51 In particular, skeptics typically
argue that Beijing would be most likely to abandon this pledge if China were
in danger of losing a war over Taiwan—an outcome that could jeopardize
the continued rule of the Chinese Communist Party.52 If, in this circum-
In
stance, China attacked critical U.S. early-warning assets—satellites,
particular—in an effort to help its conventional ballistic missiles penetrate
NOI. defenses, Washington might conclude that desperate Chinese leaders
were preparing limited nuclear strikes, against either the United States or re-
gional targets.53
Again, much would depend on context. The likelihood of misinterpreted
warning would probably increase if, in addition to attacking dual-use U.S.
enabling capabilities, China had dispersed or alerted nuclear-armed missiles.
Although this step could be a standard defensive precaution to protect the
missiles’ survivability in a major conºict, it might also exacerbate concerns in
Washington about the possibility of Chinese ªrst use. Some nuclear-armed
medium-range DF-21A ballistic missiles appear to be targeting U.S. assets in
the West Paciªc.54 The alerting of these missiles could be seen by the United
States, Perciò, as preparations for regional nuclear strikes. The alerting of
51. These concerns are strongly suggested, although not stated explicitly, in U.S. Department of
Defense, “Nuclear Posture Review,” p. 32.
52. Mark Schneider, “The Nuclear Doctrine and Forces of the People’s Republic of China”
(Fairfax, Va.: National Institute Press, novembre 2007), pag. 7–8, http://www.nipp.org/wp-
content/uploads/2014/12/China-nuclear-ªnal-pub.pdf.
53. Early in a conºict, probable Chinese attacks on regional missile-defense radars would likely be
less escalatory, because China would probably not be facing defeat then and because such radars
are not critical to nuclear operations. The PAVE PAWS radar in Taiwan is a special case and dis-
cussed below.
54. Because certain Chinese missile brigades (notably, IL 807 brigade in Anhui, but also perhaps
IL 810 brigade in Liaoning and the 816 brigade in Jilin) are not within range of important Russian
or Indian targets, it is difªcult to see what other role they could serve. See Jeffrey Lewis, Paper
Tigers: China’s Nuclear Posture, Adelphi 446 (Abingdon, U.K.: Routledge for the International Insti-
tute for Strategic Studies, 2014), P. 116. See also U.S. Department of Defense, “Nuclear Posture
Review,” p. 31.
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International Security 43:1 72
China’s ICBM force, meanwhile, could be interpreted as an attempt to threaten
the U.S. homeland and so deter nuclear retaliation to Chinese ªrst use against
regional targets. The escalation pressures might be more serious still if China
had conducted extensive attacks against U.S. ISR assets, denying the United
States contextual information that might be helpful in interpreting Chinese
intentions correctly.
how the united states might respond to misinterpreted warning.
The United States’ response to misinterpreted warning would probably de-
pend on a range of factors, including its assessment of the likelihood of nuclear
use by the adversary. Nonetheless, an overriding consideration would proba-
bly be to deter such use or, if deterrence failed, to limit the damage that the
United States would suffer in a nuclear war—a goal explicitly articulated in
IL 2018 Nuclear Posture Review.55 As such, misinterpreted warning could
lead to at least three general types of U.S. risposta; none of which is mutually
exclusive and all of which could spark further escalation.
First and most immediate, the United States would probably seek to protect
surviving elements of its nuclear C3I system because of their importance to
damage-limitation efforts, including counterforce attacks and missile defense
operations. As described below, for these efforts to have any hope of success,
the United States would have to preserve much more than just the relatively
basic capability needed to transmit employment orders to survivable nuclear
forces. Steps to preserve surviving C3I capabilities could prove escalatory. For
esempio, the United States might attack ASAT weapons that it believed could
threaten important U.S. satellites. If these weapons were located deep inside
China or Russia, then such attacks could spark escalation, especially if the
United States had previously avoided striking far inside its adversary’s bor-
ders in an effort to keep the war limited. Alternatively, or additionally, IL
United States could launch tit-for-tat strikes against equivalent Chinese or
Russian enabling assets in an attempt to coerce Beijing or Moscow into ceasing
attacks on U.S. C3I assets—potentially leading the adversary to fear for the
survivability of its nuclear forces and generating crisis instability.
Secondo, misinterpreted warning might prompt the United States to alert
bombers and send additional ballistic missile submarines (SSBNs) to sea. Al-
though neither China nor Russia could hope to disarm the United States, both
could plausibly threaten U.S. submarines in port and bombers at their bases. In
consequence, enhancing the survivability of these platforms might seem
55. NOI. Department of Defense, “Nuclear Posture Review,” p. 23.
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Escalation through Entanglement 73
to Washington like a sensible precaution. If the adversary were not planning to
use nuclear weapons, Tuttavia, this precaution could appear to be threatening.
In particular, Beijing or Moscow might worry about the possibility of attacks
with very short warning times launched from forward-deployed stealthy
bombers or from SSBNs ªring SLBMs on depressed trajectories from near its
coasts. In turn, China or Russia might respond by taking steps to enhance the
survivability of its nuclear forces, such as dispersing mobile missiles, Quale
could appear to conªrm Washington’s fears. In this way, misinterpreted warn-
ing and crisis instability could exacerbate each other.
Third, the United States could threaten to use—or even use—nuclear weap-
ons in response to misinterpreted warning. Following attacks on dual-use U.S.
C3I assets, Washington might threaten to use nuclear weapons if the attacks
continued or if the adversary employed nuclear weapons. Such a threat, how-
ever, could trigger an escalation cycle similar to the one that might be sparked
by the dispersal of U.S. SSBNs and bombers. Alternatively, if the adversary did
not judge the threat to be credible and continued to attack U.S. C3I assets, IL
United States might feel compelled to follow through on its threat and resort to
nuclear use. Although it could attempt a disarming ªrst strike, the limited use
of nuclear weapons would probably be more likely. NOI. leaders—mirroring
the precise logic that
they were ascribing to their Chinese or Russian
counterparts—might hope that such strikes would terrify the adversary into
complying with U.S. demands.
It is even possible that the United States would respond directly to attacks
on dual-use C3I assets with the use of nuclear weapons, without ªrst issuing a
nuclear threat. Although such a response would be disproportionate and thus
unlikely, Washington might feel that having threatened, in the 2018 Nuclear
Posture Review, to use nuclear weapons in this eventuality, it had to follow
through or else risk damaging its credibility and very undermining other ele-
ments of U.S. declaratory policy.56
the damage-limitation window
Although all nuclear operations require C3I capabilities, the enabling require-
ments for damage-limitation operations would be particularly demanding.
Signiªcant damage to a state’s nuclear C3I system would preclude any possi-
56. For an analysis of why immediate nuclear use would be disproportionate, see James Acton,
“Command and Control in the Nuclear Posture Review: Right Problem, Wrong Solution,” War on
the Rocks, Febbraio 5, 2018, https://warontherocks.com/2018/02/command-and-control-in-the-
nuclear-posture-review-right-problem-wrong-solution/.
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International Security 43:1 74
bility of such operations being effective. Because many enabling capabilities
are dual use and could be attacked or threatened in a conventional war, a state
with a damage-limitation doctrine might conclude that it had only a narrow
window of opportunity near the start of a conºict in which it could realistically
try to attack its opponent’s nuclear forces and to defend against whatever it
failed to destroy. Fear that this damage-limitation window might close could
create pressures for the state to conduct counterforce strikes preemptively or,
more likely, initiate aggressive military operations to try to preserve the option
of conducting damage-limitation operations later on.57
These escalation pressures differ from those created by crisis instability in
that escalation would be motivated by the goal of holding an adversary’s nu-
clear forces at risk, not of ensuring the survivability of the state’s own forces.
Although there are some similarities between the damage-limitation window
and misinterpreted warning—particularly in that they might spark aggressive
efforts to protect surviving C3I capabilities—there is one critical difference.
Escalation driven by fear of the damage-limitation window’s closing stems
from the unavoidable possibility that a war between two nuclear-armed states
might ultimately turn nuclear and could be felt even if neither state believed
its adversary was currently preparing for nuclear use.
Damage-limitation operations would consist of counterforce attacks, backed
up by missile defenses. The United States openly acknowledges that it plans
for counterforce attacks. Speciªcally, according to the 2013 “Report on Nuclear
Employment Strategy of the United States,” the most recent authoritative pub-
lic statement on U.S. targeting policy, “guidance requires the United States to
maintain signiªcant counterforce capabilities against potential adversaries.”58
Nel frattempo, Washington appears to assume that Moscow might also launch
counterforce attacks. By contrast, there is no evidence that Beijing contem-
plates such attacks, not least because it lacks the capability to conduct them on
a meaningful scale. Fear of the damage-limitation window’s closing, Perciò,
could generate escalation pressures on Russia but not China—though this sec-
tion again focuses on the United States.
57. Charles L. Glaser and Steve Fetter observe, in a parallel line of reasoning, that the possibility of
an adversary alerting its nuclear forces could create escalation pressures by complicating damage-
limitation operations. See Glaser and Fetter, “Should the United States Reject MAD? Damage Lim-
itation and U.S. Nuclear Strategy toward China,” International Security, Vol. 41, No. 1 (Estate
2016), pag. 61–62, doi:10.1162/ISEC_a_00248.
58. NOI. Department of Defense, “Report on Nuclear Employment Strategy of the United States
Speciªed in Section 491 Di 10 U.S.C.” (Washington, D.C.: NOI. Department of Defense, Giugno
2013), P. 4, http://www.defense.gov/Portals/1/Documents/pubs/ReporttoCongressonUSNuclear
EmploymentStrategy_Section491.pdf.
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Escalation through Entanglement 75
The importance of C3I capabilities to damage-limitation operations is
difªcult to overstate. Attacking dispersed mobile missiles would be partic-
ularly challenging. Despite much debate among U.S. strategists about how
effective such efforts might prove, there is no disagreement that without high-
quality ISR to detect and track missiles, along with fast and reliable communi-
cations to relay targeting data, they would be certain to fail.59 Anti-submarine
warfare operations by the United States against an enemy’s SSBNs would also
beneªt from sophisticated enabling capabilities. Such efforts would be more
likely to succeed if the operations of U.S. aircraft, surface ships, and attack sub-
marines were coordinated, and if these platforms could share information,
placing a premium on high-bandwidth communications. Nel frattempo, early-
warning capabilities would enable U.S. ICBMs to be launched before they
were destroyed by a large-scale Russian nuclear strike (potentially enabling
the United States to target any nuclear forces held in reserve by Russia). Early-
warning capabilities would also be important because of their role in both re-
gional and homeland missile defense operations. È interessante notare, in this way, IL
existence of missile defenses is not guaranteed to reduce time pressure on
the United States to act, but can, in some circumstances, actually increase it.
Even during the Cold War, when many enabling capabilities were reserved
exclusively for nuclear operations and were largely invulnerable to an adver-
sary’s nonnuclear weapons, there was concern that nuclear threats to C3I as-
sets could create escalation pressures by threatening to preclude damage
limitation.60 Today, this escalation risk is magniªed by the possibility that such
assets could be degraded, through incidental attacks, over the course of a con-
ventional war.
The possibility of U.S. damage-limitation operations becoming infeasible
could spark serious concern in Washington. In extremis, the United States
might respond by launching counterforce attacks preemptively, while its C3I
capabilities were still intact. In less extreme circumstances, it might initiate
59. For recent contributions to this debate see, Per esempio, Glaser and Fetter, “Should the United
States Reject MAD?” pp. 63–70; Austin Long and Brendan Rittenhouse Green, “Stalking the Secure
Second Strike: Intelligenza, Counterforce, and Nuclear Strategy,” Journal of Strategic Studies, Vol. 38,
Nos. 1–2 (2015), pag. 38–73, doi:10.1080/01402390.2014.958150; and Keir A. Lieber and Daryl G.
Press, “The New Era of Counterforce: Technological Change and the Future of Nuclear Deter-
rence,” International Security, Vol. 41, No. 4 (Primavera 2017), pag. 9–49, https://doi.org/10.1162/
ISEC_a_00273.
60. Robert Jervis, The Meaning of the Nuclear Revolution: Statecraft and the Prospect of Armageddon
(Ithaca, N.Y.: Cornell University Press, 1989), P. 165. For a Cold War analysis of how attacks on C3I
capabilities could blunt the effectiveness of nuclear operations, see Ashton B. Carter, “Assessing
Command System Vulnerability,” in Carter, John D. Steinbruner, and Charles A. Zraket, eds., Man-
aging Nuclear Operations (Washington, D.C.: Brookings Institution Press, 1987), pag. 555–610.
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International Security 43:1 76
escalatory military operations, such as those described above, to protect these
capabilities and hence preserve the option of conducting counterforce opera-
tions at a later time. As with misinterpreted warning, the United States could
also threaten that further attacks against key U.S. C3I capabilities would pre-
cipitate a nuclear response. If attacks continued, it might follow through on
this threat.
crisis instability
Crisis instability could be induced by threats to the survival of a state’s nuclear
forces or their enabling capabilities.61 In assessing the signiªcance of such
threats, the “key question,” argues Caitlyn Talmadge, “would not be whether
the target state expected to suffer complete nuclear disarmament . . . [Ma
whether it] feared the erosion of its nuclear capabilities past some threshold
considered vital to its security.”62 (In the general political science literature, IL
term “crisis instability” is often used in a somewhat different sense to describe
the tendency to resort to the use of force in a crisis.)
In the Cold War, analysts generally assumed that if crisis instability led to
nuclear ªrst use, such use would be in the form of a large-scale preemptive
ªrst strike. Today, if the United States or, much more likely, Russia felt its nu-
clear forces or associated C3I capabilities to be in severe danger (whether from
nuclear or nonnuclear threats), it might conceivably launch such a strike.
Other responses, Tuttavia, would probably be much more likely—including
by China, which lacks the capability for effective large-scale preemption.63 For
esempio, a state might enhance the survivability of its nuclear forces by dis-
persing mobile weapons. The national leadership might pre-delegate nuclear
launch authority to ªeld commanders. To try to scare its opponent into back-
ing down from threatening its nuclear forces, a state might threaten to use nu-
clear weapons or even use them in a limited way.64 All of these steps could
spark further escalation, albeit with varying likelihoods.
The possibility that nonnuclear operations might induce crisis instability
was ªrst discussed by scholars toward the end of the Cold War, in part because
61. The literature on crisis stability is vast, but the seminal discussion is Thomas C. Schelling, IL
Strategy of Conºict (Cambridge, Massa.: Stampa dell'Università di Harvard, 1960), chap. 9. For the concept’s
historical origins, see Michael S. Gerson, “The Origins of Strategic Stability: The United States and
the Threat of Surprise Attack,” in Elbridge A. Colby and Gerson, eds., Strategic Stability: Contro-
tending Interpretations (Carlisle, Pa.: NOI. Army War College Press, 2013), chap. 1, http://www
.strategicstudiesinstitute.army.mil/pubs/download.cfm?q(cid:2)1144.
62. Talmadge, “Would China Go Nuclear?” p. 63; see pp. 57–64 more generally.
63. Michael S. Gerson, “No First Use: The Next Step for U.S. Nuclear Policy,” International Security,
Vol. 35, No. 2 (Autunno 2010), pag. 35–39, doi:10.1162/ISEC_a_00018.
64. Talmadge, “Would China Go Nuclear?” pp. 58–59.
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Escalation through Entanglement 77
of the potential for such operations to degrade C3I capabilities. Most sig-
niªcantly, in his 1991 study, Inadvertent Escalation, Posen argued that, as the
Soviet early-warning network was degraded over the course of a conventional
war in Europe, Moscow might come to believe that the United States was
about to decapitate the Soviet nuclear C3I system and launch a preemptive
ªrst strike.65 At about the same time, Bruce Blair identiªed the vulnerability of
the U.S. nuclear C3I system to Soviet nonnuclear weapons as another potential
trigger of crisis instability.66
More recently, scholarly discussions of the implications of C3I vulnerability
for crisis instability have focused on the possibility of U.S. nonnuclear attacks
on Chinese C3I capabilities located in the theater of operations—in particular,
the communication system for China’s land-based mobile missiles, but also
its air-defense radars.67 Other C3I assets, including Chinese and Russian early-
warning capabilities and U.S. communication capabilities, are also entangled,
creating escalation risks that have not been identiªed before in the aca-
demic literature.
Russia has developed various capabilities to provide early warning of an
incoming attack with nuclear-armed ballistic missiles. China, meanwhile, ap-
pears to be in the process of doing so. One potential purpose of such capabili-
ties is to enable a state to launch nuclear weapons before they are destroyed.
Russian nuclear doctrine is generally believed to include this option, known as
“launch under attack” or “launch on warning” (neither term has a universally
accepted deªnition, although the United States adopts the former in describ-
ing its own policy). There is evidence, including in the 2013 edition of Science
of Military Strategy, a textbook published by the People’s Liberation Army
Academy of Military Sciences, that China may be moving in the same direc-
zione (though if so, it may be planning to alert its forces in a crisis rather than
keep them on day-to-day alert).68 Separately, both states have extensive air-
65. Posen, Inadvertent Escalation, chaps. 2–3. See also Bruce G. Blair, The Logic of Accidental Nuclear
War (Washington, D.C.: Brookings Institution Press, 1993), pag. 270–271.
66. Bruce G. Blair, Strategic Command and Control: Redeªning the Nuclear Threat (Washington, D.C.:
Brookings Institution, 1985), pag. 207, 296–297; and Bruce G. Blair, “Alerting in Crisis and Conven-
tional War,” in Carter, Steinbruner, and Zraket, Managing Nuclear Operations, pag. 107–108.
67. On attacks against communication assets, see Chase, Erickson, and Yeaw, “Chinese Theater
and Strategic Missile Force Modernization and Its Implications for the United States,” pp. 105–106;
Pollack, “Emerging Strategic Dilemmas in U.S.-Chinese Relations,” pp. 57–58; Christensen, "IL
Meaning of the Nuclear Evolution,” p. 468; Cunningham and Fravel, “Assuring Assured Retalia-
zione,” pp. 42, 44; and Talmadge, “Would China Go Nuclear?” pp. 78–79. On attacks against air de-
fenses, see Talmadge, “Would China Go Nuclear?” pp. 78–79.” On attacks against air defenses, Vedere
Talmadge, “Would China Go Nuclear?” pp. 77–78.
68. Gregory Kulacki, “The Chinese Military Updates China’s Nuclear Strategy” (Cambridge,
Massa.: Union of Concerned Scientists, Marzo 2015), P. 4, http://www.ucsusa.org/sites/default/
ªles/attach/2015/03/chinese-nuclear-strategy-full-report.pdf.
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International Security 43:1 78
defense systems, which probably play an important role in protecting their nu-
clear forces and associated C3I capabilities from the perceived threat of nuclear
or nonnuclear attack by U.S. aircraft and cruise missiles.
At least three types of Chinese or Russian early-warning assets are already
entangled—or could become entangled—and, Perciò, might be subject to
incidental attacks by the United States, with the consequent risk of crisis insta-
bility. Primo, the United States might target China’s or Russia’s small collection
of over-the-horizon radars, which can detect some threats at much greater
distances than conventional line-of-sight radars.69 As other analysts have
noted, the United States might have a variety of incentives, in a conventional
conºict, to strike these radars—especially, perhaps, Chinese ones with a role in
locating U.S. aircraft carriers.70 What has not been noted before (at least in the
context of a discussion of escalation risks) is that China and Russia appear to
regard their over-the-horizon radars as perhaps their best means of gaining at
least some warning of a U.S. attack with stealthy aircraft or cruise missiles,
which they worry pose a serious threat to the survivability of their nuclear
forces.71 The loss of these radars, Perciò, could be particularly disquieting to
Beijing or Moscow.
Secondo, an even more serious escalation risk that appears to have gone en-
tirely unnoticed by analysts is incidental attacks on BMEWRs—particularly
the network of these radars that rings Russia. These dual-use radars are proba-
bly Russia’s most important assets for space situational awareness up to a few
thousand kilometers in altitude and so enable Russia to hold numerous U.S.
satellites at risk.72 In consequence, the United States could strike this network
69. Pavel Podvig, “Russia Begins Deployment of Over-the-Horizon Radars,” Russian Strategic Nu-
clear Forces blog, Dicembre 3, 2013, http://russianforces.org/blog/2013/12/russia_begins_
deployment_of_ov.shtml; and Ofªce of the Secretary of Defense, “Military and Security Develop-
ments Involving the People’s Republic of China 2014,” annual report to Congress (Washing-
ton, D.C.: NOI. Department of Defense, 2014) pag. 40, 69, http://www.defense.gov/Portals/1/
Documents/pubs/2014_DoD_China_Report.pdf.
70. Twomey, “Asia’s Complex Strategic Environment,” p. 64. Of the two types of over-the-horizon
radars, skywave and groundwave, the former could have a role in detecting both ships and air-
breathing threats.
71. Zhou Wanxing, “Tianbo Chaoshiju Leida Fazhan Zongshu” [Summary of the development of
Skywave over-the-horizon radar], Journal of Electronics, Vol. 39, No. 6 (2011), pag. 1375–1376 (in Chi-
nese; the author thanks Tong Zhao for translating the relevant section of this article); Podvig,
“Russia Begins Deployment of Over-the-Horizon Radars”; and “I See You: Russian-Made Sun-
ºower Radar Is Capable of Detecting F-35 Jets,” Sputnik, Luglio 2, 2016, http://sputniknews.com/
science/20160702/1042341025/russia-podsolnukh-radar-f35.html.
72. Pavel Podvig, “Status of the Russian Early-Warning Radar Network,” Russian Strategic Nuclear
Forces blog,
Gennaio 13, 2013, http://russianforces.org/blog/2013/01/status_of_the_russian
_early-warning.shtml.
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Escalation through Entanglement 79
in an effort to protect its satellites. Such attacks could generate severe crisis in-
stability, given Russia’s reliance on launch under attack.
At least two Chinese BMEWRs can be identiªed from publicly available sat-
ellite imagery—although it is unclear how many such radars China possesses
or how many it ultimately intends to construct.73 Chinese BMEWRs have an
inherent capability to contribute to space situational awareness and hence en-
able ASAT operations, making them potential U.S. targets. Inoltre, China
may be building BMEWRs to enable the switch to a launch-under-attack pos-
ture. If it does so, China could view U.S. strikes against those radars as an
attempt to undermine the survivability of its nuclear forces.
Other technological developments could exacerbate the escalation risks as-
sociated with attacks on BMEWRs yet further. Today, Chinese and Russian
BMEWRs would be generally incapable of tracking most U.S. nonnuclear
weapons, such as aircraft and cruise missiles (not least because of the relatively
low altitude at which such weapons ºy). The United States, Tuttavia, is con-
sidering acquiring long-range nonnuclear ballistic missiles, which could be
tracked by BMEWRs.74 If the United States decides to deploy nonnuclear bal-
listic missiles, it might attack such radars, in a conºict, to suppress Chinese or
Russian defenses.
Third, for a similar reason, NOI. strikes against Russian or possible Chinese
early-warning satellites, which seem unlikely today, could become more
plausible in the future. Since November 2015, Russia has deployed two satel-
lites as part of a new space-based early-warning system, and it has ambitious
plans to deploy “about ten” by 2020.75 Even if such plans are only partially re-
alized, Russia may signiªcantly increase its reliance on space-based early
warning. Nel frattempo, the U.S. Department of Defense assesses that China also
has an interest in acquiring early-warning satellites.76 In fact, according to me-
73. These were identiªed by Catherine Dill and are located at 46.528085°N, 130.755181°E (In
Heilongjiang) and 30.286637°N, 119.128591°E (in Zhejiang). Given its location, a similar radar at
41.641422°N, 86.237161°E (in Xinjiang) is probably used for monitoring China’s own testing activi-
ties. Author’s personal communications with Catherine Dill and Jeffrey Lewis, 2016–2018.
74. A requirement in the Fiscal Year 2018 NOI. National Defense Authorization Act is likely to in-
volve the Department of Defense studying the feasibility of converting missile-defense intercep-
tors into land-attack ballistic missiles. See National Defense Authorization Act for Fiscal Year 2018,
Public Law 115-91, 115th Cong., 1st sess. (Dicembre 12, 2017), sec. 1243.(C).(2).
75. William Graham, “Soyuz 2-1B Launches Tundra Missile Detection Spacecraft,” nasaspaceºight
.com, May 25, 2017, https://www.nasaspaceºight.com/2017/05/soyuz-2-1b-launches-tundra-
missile-detection-spacecraft/; and “Russia to Launch Ten Missile Attack Warning Satellites by
2020,” TASS, Dicembre 20, 2016, http://tass.com/defense/920880.
76. Ofªce of the Secretary of Defense, “Military and Security Developments Involving the Peo-
ple’s Republic of China 2017,” p. 61.
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International Security 43:1 80
dia reports China had developed plans, by as early as 2014, to deploy its ªrst
such satellite.77 For the time being, Russian and possible Chinese satellites may
not contribute enough to nonnuclear military operations for them to become
plausible targets of incidental U.S. strikes. If, Tuttavia, the United States de-
ploys nonnuclear ballistic missiles or hypersonic boost-glide weapons, Quale
such satellites could track, that calculus could change, creating additional po-
tential triggers of crisis instability.78
Even more dramatically, over the next decade or two, actual or threatened
nonnuclear attacks by Russia against the United States could generate crisis in-
stability, most likely by incidental strikes against dual-use U.S. communication
capabilities. (In the more distant future, if China develops signiªcant counter-
force capabilities, it too could generate crisis instability through such attacks,
though that possibility is not considered further here.)
The United States has acknowledged three “layers” of capabilities for send-
ing employment orders to deployed nuclear forces: satellites, ground-based
transmitters, and airborne transmitters.79 The two U.S. satellite constellations
for communicating with nuclear forces—the legacy Milstar system and newer
AEHF system—are dual use. Because these satellites are in high-altitude geo-
stationary orbits, there would be particular challenges in attacking them (In-
cluding the possibility of evasive maneuvering by the target satellite in the
time required for a direct-ascent weapon to reach it after launch). Such chal-
lenges notwithstanding, these satellites are likely to be vulnerable soon—
if they are not already.80 Russia has reportedly preserved—and may be
enhancing—legacy Soviet direct-ascent ASAT weapons able to reach geosta-
tionary orbit and, In 2015, demonstrated an apparent co-orbital capability
against satellites in that orbit.81
The United States also operates two networks of dual-use ground-based
77. “China Plans to Launch Test Satellite for Missile Defense,” Japan Economic Newswire, agosto
24, 2015.
78. Infatti, media reports claim that both China’s and Russia’s early-warning satellites have the
capability to contribute to missile-defense operations. See ibid.; and Graham, “Soyuz 2-1B
Launches Tundra Missile Detection Spacecraft.”
79. It is possible that the United States has additional classiªed systems. Because only a handful of
technologies can communicate over long distances, Tuttavia, any such systems would be likely to
suffer from vulnerabilities similar to those of acknowledged systems.
80. The U.S. intelligence community assesses that “Russian and Chinese destructive ASAT weap-
ons probably will reach initial operational capability in the next few years.” This wording may
suggest that nondestructive ASAT weapons may already be operational. See Coates, “Worldwide
Threat Assessment of the U.S. Intelligence Community,” p. 13.
81. Brian Weeden, “Dancing in the Dark Redux: Recent Russian Rendezvous and Proximity Oper-
ations in Space,” Space Review, ottobre 5, 2015, http://www.thespacereview.com/article/2839/1;
and Arbatov, Dvorkin, and Topychkanov, “Entanglement as a New Security Threat,” pp. 33–35.
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Escalation through Entanglement 81
transmitters that it can use to send employment orders to nuclear forces. IL
Fixed Submarine Broadcast System appears to comprise nine transmitters lo-
cated mostly around the peripheries of the Atlantic and Paciªc Oceans.82 The
High Frequency Global Communications System for communicating with
bombers (and perhaps other nuclear delivery systems, pure) consists of thirteen
transmitters spread across the globe.83 All of these transmitters are large ªxed
structures that (with one exception) are located near coasts, making them vul-
nerable to Russian sea- and air-launched cruise missiles, in particular.84
In a conventional conºict against NATO, Moscow might attack U.S. commu-
nication assets in an effort to further its warªghting goals. Russian strategists
“can hardly imagine [such a] conºict failing to spread from the Euro-Atlantic
region to the Far East-Paciªc.”85 As a result, even in a European conºict,
Russia might not limit its attacks to U.S. communication assets located in or
around Europe. Infatti, Russia could plausibly launch incidental strikes (most
likely in a series of waves) against dual-use land-based transmitters spread
around the Euro-Atlantic and Asia-Paciªc areas, E, even more signiª-
cantly, against perhaps three out of the four AEHF satellites (depending on
exactly how the constellation is conªgured after Milstar satellites are retired).
Washington would surely have little conªdence that any remaining space-
and land-based assets for communicating with nuclear forces would survive
for long.
In this scenario, the United States would become critically dependent on
E-4B and E-6B aircraft, which are designed to protect national and military
leaders and facilitate communications with both nuclear and nonnuclear
forces.86 Indeed, a recent U.S. Strategic Command exercise, Global Thunder
2018, involved an adversary’s attacking U.S. nuclear C3I assets until “the last
thing remaining [era] the jet.”87 For now, these aircraft would likely be surviv-
82. NOI. Department of the Navy, “Submarine Communications Master Plan.”
83. Dwayne Harris, “HFGCS Status” (Boston: Rockwell Collins, Febbraio 4, 2010), P. 5,
http://www.hªndustry.com/meetings_presentations/presentation_materials/2010_feb_hªa/
presentations/HFGCS_HFIA_Feb_2010.pdf.
84. The exception is a High Frequency Global Communications System transmitter in Nebraska.
Given its location, Tuttavia, it is unlikely to be involved in directing operations involving forward-
deployed aircraft.
85. Alexei Arbatov, “Gambit or Endgame? The New State of Arms Control” (Moscow: Carnegie
Moscow Center, Marzo 2011), P. 6, http://carnegieendowment.org/ªles/gambit_endgame.pdf.
86. Ofªce of the Deputy Assistant Secretary of Defense for Nuclear Matters, “Nuclear Matters
Handbook 2016” (Washington, D.C.: Ofªce of the Deputy Assistant Secretary of Defense for
Nuclear Matters, 2016), P. 75, https://www.acq.osd.mil/ncbdp/nm/NMHB/docs/NMHB_2016-
optimized.pdf.
87. Quoted in Sydney J. Freedberg Jr., “When the Football Comes Out, Who Watches the Presi-
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International Security 43:1 82
able, because they could probably be protected by friendly forces while operat-
ing from U.S. airspace.
The survivability prospects of E-4B and E-6B aircraft over the longer term,
Tuttavia, are questionable. Because these aircraft use modiªed commercial
airframes, they lack both the speed to escape threats and the stealth character-
istics to avoid detection. Infatti, given that their fundamental purpose is com-
munications, their eventual replacements could not be stealthy either. Russia,
Perciò, may be able to develop capabilities, such as long-range air-to-air
weapons, that could threaten communication aircraft, even while operating
over the United States. If so, incidental attacks on these aircraft—or even, per-
può darsi, apparent preparations for such attacks—could generate crisis instability
by appearing to be an attempt to undermine the U.S. nuclear deterrent by
cutting off the ability of national leadership to communicate with deployed
nuclear forces.
escalation redux
Misinterpreted warning, the damage-limitation window, and crisis instability
are not mutually exclusive. Multiple escalation pressures could arise simulta-
neously and even interact with one another. That said, for escalation to occur
along any pathway, speciªc technological and doctrinal conditions would
have to be fulªlled, as summarized in table 1. In abstract terms, each mecha-
nism involves an “attacker” that launches or threatens nonnuclear attacks
against a “target.” Some conditions are necessary for the target to experience
pressures to escalate the conºict. Others are contributory in that they increase
the likelihood of escalation, but escalation can occur even if they are not ful-
ªlled. Per esempio, the target must have dual-use C3I capabilities, and those
capabilities must be attacked or threatened for misinterpreted warning to oc-
cur. If the attacker has a counterforce nuclear doctrine (as Russia does), escala-
tion is more likely. Nonetheless, escalation can still occur if the attacker does
not plan for counterforce operations (as in the case of China).
Early Warning: Technical Vulnerabilities and Their Consequences
Two questions arise when assessing the severity of the escalation risks de-
scribed above. Primo, how important to nonnuclear warªghting are the assets
involved in nuclear C3I? The more important they are, the more likely they
dent?” Breaking Defense, novembre 9, 2017, https://breakingdefense.com/2017/11/stratcom-
wargames-its-own-death-who-watches-the-president/.
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Escalation through Entanglement 83
Tavolo 1. Technological and Doctrinal Conditions for Escalation to Occur as a Result of
Entanglement
Misinterpreted
Warning
Damage-Limitation
Window
Crisis
Instability
Target’s nuclear forces have been
attacked by—or are perceived to be
threatened by—attacker’s nonnuclear
weapons
Target’s nuclear C3I (command,
controllo, communication, E
intelligence) capabilities have been
attacked by—or are perceived to be
threatened by—attacker’s nonnuclear
weapons
Target’s nuclear delivery systems
are dual use or superªcially similar
to nonnuclear delivery systems
Target’s nuclear C3I capabilities are
dual use
Attacker’s nuclear doctrine calls for
damage limitation
Target’s nuclear doctrine calls for
damage limitation
Attacker’s conventional warªghting
doctrine calls for attacks against C3I
capabilities
(cid:3)(cid:3)
(cid:3)(cid:3)
(cid:3)(cid:3)
(cid:3)(cid:3)
(cid:3)
(cid:3)
(cid:3)
(cid:3)(cid:3)
(cid:3)
(cid:3)(cid:3) (cid:2) necessary condition
(cid:3) (cid:2) exacerbating condition
aAt least one of these conditions is necessary for crisis instability.
(cid:3)(cid:3)UN
(cid:3)(cid:3)UN
(cid:3)
(cid:3)
(cid:3)
(cid:3)
might be threatened or attacked in a conventional conºict. Secondo, how badly
would strikes against dual-use enabling capabilities degrade the target’s abil-
ity to prosecute a nuclear war? If the target’s nuclear C3I system were highly
resilient and limited strikes would do little to undermine its overall effective-
ness, then the escalation risks of incidental strikes would probably be small. By
contrasto, if the loss of a few key enabling assets—in the worst case, just one—
severely undermined the target’s ability to conduct nuclear operations, escala-
tion would be more likely.
This section demonstrates that the United States’ early-warning system is
deeply integrated into its conventional operations and that even limited strikes
could lower its effectiveness signiªcantly and so create serious escalation risks.
Separately, it considers the risks of cyber interference with dual-use Chinese,
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International Security 43:1 84
Russian, and U.S. early-warning capabilities. These risks have some important
differences from those that might result from kinetic strikes.
Threats to early-warning assets are important in generating escalation risks
through crisis instability, misinterpreted warning, and in the cases of Russia
and the United States, the damage-limitation window. For reasons of space,
threats to other enabling capabilities are not considered here, though are po-
tentially no less signiªcant. Infatti, in a real conºict, it is possible that multiple
enabling systems could be attacked or threatened—potentially very early in a
conºict, especially where ISR is concerned—magnifying escalation risks.
As with Russia, early warning would be necessary for the United States to
execute any of the launch-under-attack options included in its nuclear war
plans.88 Under its policy of “dual phenomenology,” Washington requires “two
independent information sources using different physical principles” in as-
sessing a potential attack.89 To this end, the United States has deployed two
distinct missile early-warning capabilities.90 Space-based infrared detectors
can identify the hot gases that are expelled from a ballistic missile while its
motor is ªring. Later in ºight, large land-based radars can monitor the incom-
ing reentry vehicle, potentially from a distance of thousands of kilometers.
If U.S. launch-under-attack plans include the option to launch nuclear weap-
ons before any nuclear detonations on American soil—as was the case toward
the end of the Cold War and appears to be true today—then the United
States’ early-warning architecture has no redundancy at the systems level;
the loss of early-warning data from either satellites or radars could prevent
Washington from meeting its own requirement for dual phenomenology.91
threats to u.s. space-based early-warning assets
In 2018, the United States completed deployment of the Space-Based Infrared
System (SBIRS) to replace the legacy Defense Support Program system for
space-based early warning. The SBIRS constellation comprises six satel-
88. Bureau of Arms Control, Veriªcation, and Compliance, “U.S. Nuclear Force Posture and De-
Alerting,” fact sheet (Washington, D.C.: NOI. Department of State, Dicembre 14, 2015), https://
web.archive.org/web/20170101112527/https://www.state.gov/t/avc/rls/250644.htm.
89. Ofªce of the Deputy Assistant Secretary of Defense for Nuclear Matters, “Nuclear Matters
Handbook 2016,” p. 76.
90. Inoltre, various systems can detect the detonations of nuclear warheads, but these are less
useful for enhancing force survivability.
91. According to the U.S. Dipartimento di Stato, “The President would have less than 30 minutes in
which to make a decision to launch our ICBMs under attack.” This timeline strongly suggests that
a launch could take place before incoming warheads detonated. Bureau of Arms Control, Veriªca-
zione, and Compliance, “U.S. Nuclear Force Posture and De-Alerting.” On Cold War policy, Vedere
Blair, The Logic of Accidental Nuclear War, pag. 168, 192.
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Escalation through Entanglement 85
lites.92 Four dedicated SBIRS GEO satellites are in geostationary orbits, Di
36,000 kilometers above ªxed points near the Equator. Inoltre, to provide
coverage of the northern polar region, two more SBIRS HEO detectors are
hosted by “classiªed” satellites, whose primary purpose is reportedly elec-
tronic-intelligence collection, in highly elliptical orbits.93 These satellites spend
most of their orbits in the Northern Hemisphere, reaching latitudes as high
as 65°N.
As with U.S. communication satellites, it is likely that if SBIRS satellites are
not already vulnerable, they will be soon.94 The U.S. intelligence community
assesses that both China and Russia are “advancing directed-energy weapons
technologies for the purpose of ªelding ASAT weapons that could blind or
damage sensitive space-based optical sensors, such as those used for . . . mis-
sile defense.”95 Moreover, like Russia, China is funding the development of
direct-ascent ASAT weapons and, In 2013, probably tested an ASAT weapon
that may be capable of threating geostationary satellites.96
In a conventional conºict, an adversary could have at least two signiªcant
motivations for launching incidental attacks against the United States’ SBIRS
constellation. Primo, the electronic-intelligence collection satellites that report-
edly host SBIRS HEO detectors are in orbits ideally suited for monitoring
military activities in Russia’s north, making them potential targets. One partic-
ularly strong motivation for Moscow to attack them might be to interfere with
NOI. efforts to collect intelligence on the movements of the surface ships and
submarines of Russia’s Northern Fleet, which is based inside the Arctic Circle.
In such strikes, the SBIRS HEO detectors would be collateral damage.
Secondo, China or Russia could target the SBIRS constellation because of its
role in enabling nonnuclear operations. The constellation’s most important
92. The United States has purchased additional satellites for replenishment purposes; more than
six satellites, Perciò, may temporarily be in orbit.
93. Ofªce of the Secretary of Defense, “Report to the Defense and Intelligence Committees of the
Congress of the United States on the Status of the Space Based Infrared System Program” (Wash-
ington, D.C.: NOI. Department of Defense, Marzo 2005), P. 31, http://nsarchive.gwu.edu/
NSAEBB/NSAEBB235/42.pdf; and Michel Capderou, Handbook of Satellite Orbits: From Kepler to
GPS, trans. Stephen Lyle (Cham, Svizzera: Springer, 2014), P. 428 N. 133.
94. Attacks against ground-based uplinks or downlinks are also a threat, but are not considered
further here.
95. Coates, “Worldwide Threat Assessment of the U.S. Intelligence Community,” p. 13.
96. Brian Weeden, “Through a Glass, Darkly: Chinese, American, and Russian Anti-Satellite
Testing in Space” (Broomªeld, Colo.: Secure World Foundation, Marzo 17, 2014), pag. 4–19, https://
swfound.org/media/167224/through_a_glass_darkly_march2014.pdf; and U.S.-China Economic
and Security Review Commission, “2015 Report to Congress” (Washington, D.C.: NOI. Govern-
ment Printing Ofªce, novembre 2015), pag. 292–298, https://www.uscc.gov/sites/default/ªles/
annual_reports/2015%20Annual%20Report%20to%20Congress.PDF.
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International Security 43:1 86
such functions are providing early warning of, and cueing defenses against,
nonnuclear ballistic missiles. Generalmente, the more satellites were attacked, IL
more the performance of U.S. defenses would be degraded. SBIRS satellites are
involved in other nonnuclear missions, including “intelligence collection” and
“battlespace characterization,” which includes “battle damage assessment,
suppression of enemy air defense, [E] enemy aircraft surveillance.”97 In a
few circumstances, these auxiliary functions could be sufªciently important to
motivate an adversary to launch incidental attacks. Per esempio, China might
attack SBIRS satellites because of their ability to detect nonnuclear ballistic
missiles early in ºight and hence provide targeting data that the United States
would ªnd useful if it sought to hunt the mobile launchers from which such
missiles were being launched.98
Not only might China or Russia attack SBIRS satellites in a conventional
conºict, but such attacks—even if limited—could have serious negative im-
plications for the United States’ ability to monitor launches of the adversary’s
nuclear-armed ballistic missiles.99 With six satellites, the SBIRS constellation
can be—and, after the retirement of the remaining Defense Support Program
satellites, presumably will be—conªgured so that most areas from which
nuclear-armed missiles might plausibly be launched are monitored by at least
three or four satellites at all times, providing some margin of redundancy.
In practice, Tuttavia, this margin could be worn away quickly. If Beijing or
Moscow sought, in a conventional conºict, to undermine U.S. missile defenses
by degrading the SBIRS constellation to point where it could not monitor non-
nuclear missile launches from, rispettivamente, Eastern China or Western Russia,
the United States would also lose the capability to monitor the majority of its
adversary’s nuclear forces continuously from space.
The margin of redundancy for some potential launch sites is even thinner.
Per esempio, if Russia destroyed just two SBIRS satellites—either of the host
satellites for SBIRS HEO detectors, and the western-most SBIRS GEO satellite
(which would contribute signiªcantly to ballistic missile defense operations in
Europe)—it would deprive the United States of the space-based capability
97. Ofªce of the Secretary of Defense, “Report to the Defense and Intelligence Committees of the
Congress of the United States on the Status of the Space Based Infrared System Program,” p. 4.
98. Morgan, “Deterrence and First-Strike Stability in Space,” p. 20.
99. This discussion is based on the author’s own analysis using NASA’s General Mission Analysis
Tool orbital modeling software and data about satellite orbits from Chris Peat, Heavens Above
(website), http://www.heavens-above.com; and Jonathan McDowell, “Geostationary Orbit Cata-
log,” Jonathan’s Space Report, n.d., http://www.planet4589.org/space/log/geo.log. It assumes that,
after legacy Defense Support Program satellites have been retired, SBIRS GEO 4 will be placed in
an orbit at or near 66°E, where a Defense Support Program satellite is currently located.
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Escalation through Entanglement 87
to continuously monitor potential Russian SSBN patrol areas in the North
Atlantic Ocean close to Europe.
Inoltre, the SBIRS constellation features a single-point vulnerability: IL
United States could not continuously monitor the northern polar region from
space if either of the SBIRS HEO detectors were rendered inoperable. With just
one of these detectors in operation, there would be slightly more than four-
and-a-half hours each day during which the United States had no coverage of
the northern polar region or only partial coverage. Gen. William Shelton, Poi
commander of U.S. Space Command, was almost certainly referring to this
weakness when, In 2014, he acknowledged, without further explanation, IL
existence of a single-point vulnerability in the SBIRS constellation.100
Historically, monitoring the northern polar region has not been a U.S. prior-
ità, presumably because so much of it used to be covered by ice year round
that it was an undesirable area from which to launch ballistic missiles.101 In-
deed, until the ªrst SBIRS HEO detector was launched in 2006, the United
States relied solely on land-based radars for this task. As climate change
further reduces the sea ice coverage of the Arctic Ocean, Tuttavia, particolarmente
during summer, monitoring the northern polar region is probably becoming
more important.
threats to u.s. land-based early-warning assets
The United States operates six land-based early-warning radars designed pri-
marily to detect missile attacks against the United States: ªve PAVE PAWS ra-
dars are located in California, Massachusetts, Greenland, the United Kingdom,
and Alaska, where a COBRA DANE radar is also based.102 All of these ballistic
missile early-warning radars are large and immobile, and hence potentially
vulnerable to precise conventional weapons, including air- and sea-launched
cruise missiles. Generalmente, opening a complete hole in the U.S. network of
BMEWRs would require the destruction of at least two or three radars.103
100. William L. Shelton, “Space and Cyberspace—Foundational Capabilities for the Joint
Warªghter and the Nation,” speech at the Air Force Association Air Warfare Symposium,
Orlando, Florida, Febbraio 21, 2014, http://web.archive.org/web/20141225171206/http://www
.afspc.af.mil/library/speeches/speech.asp?id(cid:2)747.
101. Russian SSBNs reportedly had some capability to launch missiles from under relatively
thin ice. Valery E. Yarynich, “C3: Nuclear Command, Control Cooperation” (Washington, D.C.:
Center for Defense Information, May 2003), P. 147, https://www.scribd.com/doc/282622838/C3-
Nuclear-Command-Control-Cooperation.
102. Technically, after PAVE PAWS radars are upgraded to contribute to missile-defense opera-
zioni, they are renamed Upgraded Early Warning Radars. Forward-deployed missile-defense ra-
dars, such as the AN/TPY-2, could also contribute to early warning.
103. In theory, the destruction of the radar in either California or Massachusetts would create such
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International Security 43:1 88
Although the primary mission of U.S. BMEWRs is to detect and track an in-
coming nuclear strike, they also contribute signiªcantly to two nonnuclear op-
erations. Primo, they have a signiªcant role in tracking space objects, including
NOI. satellites and potentially Chinese and Russian ASAT weapons. Di conseguenza,
Beijing or Moscow might plausibly attack U.S. BMEWRs to maximize both the
effectiveness and consequences of ASAT operations.
Secondo, like early-warning satellites, the United States’ BMEWRs have (O,
in some cases, are currently being upgraded to gain) the capability to contrib-
ute to defending against nonnuclear ballistic missile strikes. Infatti, both
China and Russia evince an interest in holding ground-based U.S. ballistic
missile defense assets at risk.104 That said, today at least, only one BMEWR—
the one based at Fylingdales in the United Kingdom—could likely become
involved in defending against Chinese or Russian nonnuclear ballistic mis-
sile strikes and so be subject to incidental attacks.105 Given the location of
other U.S. BMEWRs, the only Chinese or Russian ballistic missiles that they
would be likely to track would be SLBMs or ICBMs, all of which are currently
nuclear armed.
The U.S. Fylingdales BMEWR is not only the radar most likely to suffer an
incidental attack; it is also the most important radar for providing early warn-
ing of a Russian nuclear strike. Because it is based so far east of the continental
stati Uniti, this radar could detect Russian ICBM and SLBM launches from
most deployment areas much earlier than other U.S. BMEWRs. Di conseguenza, es-
pecially if Russia succeeded in partially or completely disabling the SBIRS con-
stellation, follow-on attacks against the Fylingdales radar could be particularly
escalatory. Looking forward, if China or Russia eventually develops non-
nuclear ICBMs or SLBMs, then U.S. BMEWRs other than Fylingdales could
take on a signiªcant role in nonnuclear missile defense operations, creating
new targets for incidental attacks and thus potential triggers of escalation.
a hole, but it is currently unlikely that either of these radars and no other would be subject to inci-
dental attacks. The discussion in this section is based on the author’s own analysis using Google
Terra. The author thanks Geoffrey Forden and Pavel Podvig for assistance with, rispettivamente, visu-
alizing ballistic missile trajectories and radar fans. Data about the capabilities of U.S. BMEWRs are
available from Missile Defense Agency, “Elements: Sensors” (Washington, D.C.: NOI. Department
of Defense, Gennaio 22, 2018), https://www.mda.mil/system/sensors.html.
104. Second Artillery Corps, “The Science of Second Artillery Campaigns,” pp. 318, 396–397; E
Andrew E. Kramer, “Russian General Makes Threat on Missile-Defense Sites,” New York Times,
May 3, 2012, http://www.nytimes.com/2012/05/04/world/europe/russian-general-threatens-
pre-emptive-attacks-on-missile-defense-sites.html.
105. The author estimates that the Fylingdales radar, if angled at 3 degrees above the horizontal,
could track an Iskander ballistic missile with a range of 500 kilometers ªred from Kaliningrad to
western Poland for about 150 kilometers of its trajectory.
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Escalation through Entanglement 89
Intriguingly, there may be an Asia-Paciªc analogue to the Fylingdales
radar—even if it is not a U.S. radar. In 2013, Taiwan commissioned a PAVE
PAWS early-warning radar that it purchased from the United States. Taipei has
stated that the sole purpose of this radar is to track Chinese short-range
nonnuclear ballistic missiles.106 This radar, Tuttavia, does have an inherent ca-
pability to detect Chinese ICBMs early in ºight. Infatti, it could provide sig-
niªcantly more warning of a Chinese ICBM strike than any U.S. BMEWR, E
a senior Taiwanese lawmaker has claimed that data from this radar is shared
with the United States.107 If this claim is correct, then incidental Chinese strikes
against the radar could have signiªcant escalation consequences. To be sure,
China might attack this radar in the early phases of a conºict, while the war’s
outcome was still uncertain. At that juncture, the escalation risks would proba-
bly be modest, because China’s incentives to use nuclear weapons would be
minimal. If, Tuttavia, China began to lose the conºict and subsequently at-
tacked the United States’ SBIRS satellites, then the already serious escalation
consequences of attacking early-warning satellites would likely be com-
pounded by China’s earlier attack on the radar.
cyber threats to early-warning systems
There are credible reports of cyber interference with early-warning systems.
Most notably, when Israel destroyed Syria’s clandestine plutonium-production
reactor in 2007, it reportedly ªrst disabled the Syrian air-defense system using
a variety of tools, including cyberweapons, to reduce risks to the aircraft con-
ducting the attack.108 To be sure, nuclear C3I networks in China, Russia, E
the United States are presumably protected by much better cyber defenses
than Syria’s air-defense system was a decade ago. Nonetheless, these states
have launched efforts to enhance the cyber defenses of networks used for nu-
clear C3I, implying that they believe cyber threats to them are credible; Infatti,
the United States military has said so explicitly.109 Yet, eliminating cyber vul-
106. “Taiwan Deploys Advanced Early Warning Radar System,” Straits Times, Febbraio 3, 2013,
http://www.straitstimes.com/asia/taiwan-deploys-advanced-early-warning-radar-system.
107. “Long-Range Radar Budget Surges by NT$10 Billion,” China Post, Gennaio 6, 2013, https://
web.archive.org/web/20130108092745/http://www.chinapost.com.tw/taiwan/national/
national-news/2013/01/06/366468/Long-range-radar.htm.
108. David A. Fulghum, Robert Wall, and Amy Butler, “Cyber-Combat’s First Shot: Israel Shows
Electronic Prowess: Attack on Syria Shows Israel Is Master of the High-Tech Battle,” Aviation Week
& Space Technology, novembre 26, 2007, pag. 28–31. See also Joshua Berlinger and Juliet Perry,
“China Tried to Hack Group Linked to Controversial Missile Defense System, NOI. Cybersecurity
Firm Says,” CNN, April 27, 2017, http://www.cnn.com/2017/04/27/asia/china-south-korea-
thaad-hack/.
109. Vedere, Per esempio, Michael Pillsbury, “The Sixteen Fears: China’s Strategic Psychology,” Sur-
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International Security 43:1 90
nerabilities entirely may be impossible. The U.S. Defense Science Board, for ex-
ample, has stated baldy that it is “impossible” for the U.S. Department of
Defense to fully defend its networks.110
The existing literature on cyber threats to early-warning systems has not
considered the possibility that dual-use early-warning capabilities might be
subject to incidental cyber interference for the purpose of inºuencing the out-
come of a conventional war.111 (Because some physical early-warning assets in
China, Russia, and the United States are dual use, at least some of the net-
works that support them must also be dual use.112) The term “cyber interfer-
ence” is used here to include both cyber espionage (gathering information for
intelligence purposes without damaging the operation of the target system)
and cyberattack (attempting to undermine the target system’s functionality by
compromising the integrity or availability of its data).
The severity of the escalation risks stemming from incidental cyber interfer-
ence with early-warning capabilities depends on at least two factors. One fac-
tor, as Erik Gatrzke and Jon Lindsay note, is whether the target detects the
cyber interference.113 The other is whether, if the interference is detected,
the target correctly assesses the attacker’s intent.
vival, Vol. 54, No. 5 (October/November 2012), P. 157, doi:10.1080/00396338.2012.728351; “Cyber
Security Units to Protect Russia’s Nuclear Weapons Stockpiles,” RT, ottobre 17, 2014, https://
www.rt.com/news/196720-russia-missile-forces-cybersecurity/; and Benjamin D. Katz, “U.S.
Beefs Up Cyber Defenses to Thwart Hacks of Nuclear Arsenal,” Bloomberg, Marzo 24, 2016, https://
www.bloomberg.com/news/articles/2016-03-24/u-s-beefs-up-cyber-defenses-to-thwart-hacks-
of-nuclear-arsenal.
110. Defense Science Board, NOI. Department of Defense, “Task Force Report: Resilient Military
Systems and the Advanced Cyber Threat” (Washington, D.C.: Ofªce of the Under Secretary of De-
fense for Acquisition, Tecnologia, and Logistics, Gennaio 2013), P. 6, https://www.acq.osd.mil/
dsb/reports/2010s/ResilientMilitarySystemsCyberThreat.pdf.
111. This literature focuses on two deliberate escalation risks. Primo, a malicious third party could
try to catalyze a nuclear war between two nuclear-armed states by generating false warning of an
incoming nuclear attack. Secondo, a state planning to launch a nuclear attack might ªrst “blind” its
opponent’s early-warning system. See Global Zero Commission on Nuclear Risk Reduction, “De-
Alerting and Stabilizing the World’s Nuclear Force Postures” (Washington, D.C.: Globale
Zero, 2015), P. 30, http://www.globalzero.org/ªles/global_zero_commission_on_nuclear_risk
_reduction_report_0.pdf; Andrew Futter, Cyber Threats and Nuclear Weapons: New Questions for
Command and Control, Sicurezza, and Strategy (London: Royal United Services Institute for Defence
and Security Studies, Luglio 2016), pag. 24–25, https://rusi.org/sites/default/ªles/cyber_threats
_and_nuclear_combined.1.pdf; and Stephen J. Cimbala, “Nuclear Cyberwar and Crisis Manage-
ment,” Comparative Strategy, Vol. 35, No. 2 (2016), P. 119, doi:10.1080/01495933.2016.1176458.
112. At the very least, the networks used to determine whether an incoming weapon was conven-
tional or nuclear (and at all prior stages of the early-warning process) must be dual use.
113. Erik Gartzke and Jon R. Lindsay focus on deliberate attacks intended to undermine the tar-
get’s nuclear deterrent. The escalation dynamics resulting from those attacks and incidental at-
tacks would be different. See Gartzke and Lindsay, “Thermonuclear Cyber War,” Journal of Cyber
Sicurezza, Vol. 3, No. 1 (Marzo 2017), pag. 37–48, doi:10.1093/cybsec/tyw017.
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Escalation through Entanglement 91
In even a modest conventional conºict, a state’s temptation to conduct cyber
espionage against an enemy’s C3I system could be very strong. In caso di
dual-use early-warning networks, the state might focus on detecting its oppo-
nent’s potential weaknesses—such as radars that were inoperative or perform-
ing poorly—so the state could exploit them to enable more effective offensive
operations. Such cyber espionage could have escalation consequences only if
the target discovered it. In questo caso, the espionage could contribute to misin-
terpreted warning, because the target might believe that its opponent was
looking for weaknesses prior to using nuclear weapons. The exact conse-
quences, Anche se, would presumably depend on what the target believed
the cyber espionage had revealed. Per esempio, if Russia believed that the
United States had discovered a serious weakness in its early-warning system,
Moscow’s conªdence in the survivability of its nuclear forces could diminish,
generating crisis instability on top of misinterpreted warning. By contrast, if
Russia believed that the United States had failed to acquire anything of sig-
niªcance, the escalation consequences might be much more modest.
Cyberattacks designed to facilitate nonnuclear strikes by undermining the
operation of an adversary’s early-warning capabilities could also precipi-
tate escalation. Once again, the attack could prove escalatory only if the target
detected it. If a state did conclude that its early-warning system had been sub-
ject to a cyberattack, the escalation consequences could be as serious as if the
system had been physically attacked, especially if the target believed that
the damage could not be reversed quickly. Infatti, the consequences might
even be more serious because a cyberattack against a critical network (one re-
sponsible for fusing data from multiple sources, Dire) could disable an entire
early-warning system, whereas kinetic strikes would have to pick off sensors
one by one.
The risk of escalation could be further exacerbated by the challenges fac-
ing the target in determining the attacker’s intent. Fully understanding the
purpose of complex malware can be difªcult and time consuming, and the tar-
get might be uncertain about its capabilities for a signiªcant length of time—
allowing considerable scope for worst-case thinking. Per esempio, even if the
malware were capable only of espionage, the target might worry it also con-
tained a “kill switch” able to disable an early-warning system after activation.
To create yet more uncertainty, a single penetration into a network can be
used to insert multiple “payloads.” For this reason, even if the target believed
that ongoing interference was limited to espionage, it might worry that the
vulnerability used by the attacker could be exploited for more nefarious ends
(at least until that vulnerability had been identiªed and ªxed).
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International Security 43:1 92
In the ªnal analysis, there would be at least two important differences be-
tween the escalation risks resulting from cyber interference with and physical
attacks on dual-use early-warning systems. Primo, a physical attack on an early-
warning asset would be signiªcantly more difªcult to conceal than cyber inter-
ference (even if not all physical attacks are equally obvious). Unlike plausible
physical attacks, Perciò, cyberattacks on early-warning systems might go
undetected and have no escalation consequences. Secondo, with physical at-
tacks on early-warning assets, the risk of inadvertent escalation would stem
from the dual-use nature of the target. With cyber interference, this ambiguity
would still exist but would be compounded by possible uncertainty about the
interference’s purpose. This “double ambiguity” is a major reason why the es-
calation risks of U.S. nonnuclear operations against China or Russia would be
greater than previous academic analyses have suggested. It means that even
limited cyber espionage, if detected, could prove highly escalatory.
Policy Implications
In spite of the magnitude of the dangers, risk reduction is likely to prove ex-
tremely challenging. China, Russia, and the United States would be unlikely to
agree to meaningful limits on nonnuclear capabilities designed to threaten po-
tential adversaries’ C3I assets because each state views such capabilities as
critical for both conventional warªghting and deterrence. Inoltre, each state
is—or may become—resistant to disentangling its nuclear and nonnuclear
forces and C3I assets. Russia’s objection, according to Alexey Arbatov, is sim-
ply the ªnancial costs of separation.114 Some Chinese scholars, meanwhile,
have argued that separating nuclear and nonnuclear forces and C3I assets
could make U.S. attacks against Chinese nonnuclear capabilities less risky and
hence more likely (even if these scholars also argue that China’s adoption of
dual-use capabilities was originally motivated by convenience and not strat-
egy).115 Infatti, the same logic may even end up holding sway in Washington.
There is no evidence that the United States’ use of dual-use C3I assets (or dual-
use aircraft, for that matter) was motivated by anything other than con-
venience and cost. If, Tuttavia, there was ever a serious discussion about
114. Alexey Arbatov, “Non-Nuclear Weapons and the Risk of Nuclear War: A Russian Perspec-
tive,” discussion at the Carnegie Endowment for International Peace, Washington, D.C., Novem-
ber
2017, http://carnegieendowment.org/2017/11/29/non-nuclear-weapons-and-risk-of-
nuclear-war-russian-perspective-event-5762 (in particular, the comments at 38:44 of the recording).
115. Zhao and Li, “The Underappreciated Risks of Entanglement,” p. 68.
29,
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Escalation through Entanglement 93
separating nuclear and nonnuclear C3I then it is not difªcult to imagine advo-
cacy for entanglement on deterrence grounds.
Yet, Beijing, Moscow, and Washington should still confront the question of
whether the advantages of entanglement—both ªnancial and strategic—are
worth the escalation risks. After all, if the escalation risks are too great, Poi
any beneªts will be outweighed by an increase in the likelihood and probable
costs of a war. If this article is correct—if the escalation risks are greater than
widely realized and likely to increase further—then China, Russia, and the
United States may already be on the wrong side of the line.
understanding and raising awarness of the risks
A ªrst-order task for Washington, Beijing, and Moscow, Perciò, is to conduct
their own analyses, most likely on a classiªed basis, of the potential beneªts
and risks of entanglement. These efforts should be informed by intelligence
assessments about the extent to which potential adversaries’ nuclear and non-
nuclear forces and C3I assets are entangled, and about those rivals’ percep-
tions of the intentions and capabilities of the state conducting the analysis.
If such analyses concluded that the risks of entanglement did indeed out-
weigh the beneªts, they could catalyze and inform the development of a risk-
reduction strategy.
In principle,
there are both unilateral and cooperative approaches to
risk mitigation. Given the poor state of political relations between Washington
and Beijing, and between Washington and Moscow, unilateral measures cur-
rently represent the only feasible starting point. Such measures certainly can-
not eliminate the escalation risks of entanglement, but they could help to
mitigate them and slow their rate of increase.
In this vein, the simplest risk-reduction measure would be to raise aware-
ness, within governments and militaries, of the challenges created by entangle-
ment for assessing an adversary’s intent and, importantly, for the adversary in
assessing the state’s own intent. Given that crisis instability and misinter-
preted warning are mediated by perceptions—or rather misperceptions—
about the intent behind incidental strikes or threats, drawing the attention of
decisionmakers to the difªculties of assessing intent might encourage restraint
in a conºict and so help counteract inadvertent escalation pressures. Greater
awareness of the risks could also catalyze peacetime preparations, such as en-
hancing the survivability of C3I assets, that might reduce the dangers associ-
ated with incidental strikes should a war occur. Such preparations might
simultaneously mitigate the escalation risks resulting from the existence of
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International Security 43:1 94
the damage-limitation window (which are not driven by misjudgments
about intent).
A tal fine, China, Russia, and the United States could set up risk-reduction
teams within their defense establishments.116 Most important, during crises or
conºicts, these teams could advise national and military leaders on the risks
associated with entanglement and on ways to manage them. In peacetime,
they could be tasked with ensuring that escalation risks were factored into
both war planning and acquisition decisions for new strategic weapons and
C3I capabilities (the teams could, Per esempio, assess the different alternatives
under consideration for their escalation implications, and be entitled to pro-
pose other options or object to the program entirely).
In definitiva, Ovviamente, high-level civilian or military leaders would be
responsible for making decisions after considering escalation risks along-
side more traditional strategic, military, and ªnancial considerations. Risk-
reduction teams, Perciò, would have to be bureaucratically empowered (by
being led by a suitably senior ofªcial, Per esempio) to ensure their advice was
heard. Such teams would also beneªt by being made up from a broad range of
including civilian strategists, military planners, and intelligence
experts,
ofªcials with deep knowledge of potential adversaries’ thinking.
In addition to their other tasks, risk-reduction teams could be tasked, In
peacetime, with proposing unilateral risk-reduction measures. Changes to de-
claratory policy (which could be accomplished rapidly) and C3I system design
(which could take years to implement) are examples of two different but
complementary approaches.
declaratory policy
Declaratory policy is one tool for deterring incidental attacks on C3I assets by
underscoring the risks. It is possible that the civilian ofªcials or military of-
ªcers responsible for authorizing such attacks might not appreciate the poten-
tial for their intentions to be misinterpreted. Such ofªcials could hold very
senior positions (kinetic ASAT attacks, in particular, might require authoriza-
116. James M. Acton, “Technology, Doctrine, and the Risk of Nuclear War,” in Nina Tannenwald,
Acton, and Jane Vaynman, Meeting the Challenges of the New Nuclear Age: Emerging Risks and De-
clining Norms in the Age of Technological Innovation and Changing Nuclear Doctrines (Cambridge,
Massa.: American Academy of Arts and Sciences, 2018), pag. 54–55, https://www.amacad.org/
multimedia/pdfs/publications/researchpapersmonographs/New-Nuclear-Age_Emerging-Risks/
New-Nuclear-Age_Emerging-Risks.pdf. This idea was inspired by Posen, Inadvertent Escalation,
pag. 212–218.
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Escalation through Entanglement 95
tion from a head of state) and might not know that such assets were typically
dual use; even if they did, they might not appreciate the implications.
IL 2018 NOI. Nuclear Posture Review’s threat to use nuclear weapons in
response to attacks on nuclear C3I assets is presumably an attempt to warn
potential adversaries about these implications. The disproportionate nature of
this threat, Tuttavia, risks its being dismissed by Beijing and Moscow as blus-
ter. Invece, a somewhat vaguer formulation might ultimately prove more
effective. Per esempio, Washington could state that it considers dual-use com-
munication and early-warning assets an integral part of its nuclear C3I system
and would respond to attacks on them accordingly (Beijing and Moscow could
make similar statements). As with all declaratory policy, such statements
might
Essi
were repeated periodically by very senior ofªcials.
inºuence potential adversaries’
thinking more effectively if
toward a more resilient c3i architecture
Over the longer term, states could also develop C3I architectures that were
both less likely to be subject to incidental attacks and more survivable if they
were. Some analysts have suggested creating at least two separate C3I
systems—one for nuclear or “strategic” operations and one (or more) for all
other operations.117 Even putting the costs of this idea aside, such disaggrega-
tion would reduce risks only if Washington, Dire, could convince Beijing and
Moscow that it had separated nuclear and nonnuclear C3I functions, Quale
would be no easy task. If the United States failed to do so, disaggregation
could increase risks because the escalation consequences of China’s or Russia’s
attacking C3I assets that were involved only in nuclear operations—out of the
incorrect belief that they also enabled conventional operations—could be more
severe than the consequences of attacking dual-use assets.
A somewhat different approach for early warning would be to create space-
based capabilities that were less likely to be subject to incidental attack be-
cause they were incapable of contributing signiªcantly to any mission other
than detecting the launch of an adversary’s missiles (whether nuclear or
nonnuclear). In particular, as a matter of basic optics, physically small infrared
117. Elbridge Colby, “From Sanctuary to Battleªeld: A Framework for a U.S. Defense and Deter-
rence Strategy for Space” (Washington, D.C.: Center for a New American Security, Gennaio 2016),
P. 22, https://s3.amazonaws.com/ªles.cnas.org/documents/CNAS-Space-Report_16107.pdf; E
Todd Harrison, “The Future of MILSATCOM” (Washington, D.C.: Center for Strategic and Bud-
getary Assessments, 2013), pag. 40–42, http://csbaonline.org/uploads/documents/Future-of-
MILSATCOM-web.pdf.
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International Security 43:1 96
detectors would be incapable of producing the kind of high-resolution imag-
ery that would be most useful for cueing missile defenses and detecting the ex-
act location of mobile missile launchers.118 Because this limitation was the
result of an observable and immutable property of the hardware, Washington,
Dire, might be able to persuade Beijing and Moscow that it was real.
Another key advantage of small detectors is that they would not require
their own satellite buses (which are generally very expensive to design and
manufacture), but could instead be hosted by satellites used for other pur-
poses. In this way, it might be possible to deploy them affordably in large
numbers—tens, perhaps—creating a resilient architecture that would be the
early-warning equivalent to AFSATCOM.119 Although this author’s judgment
is that this kind of “dispersed” early-warning system would reduce the risks
associated with incidental attacks, important challenges and trade-offs that de-
serve further study would arise.
Per esempio, if the host satellites were attacked to undermine their primary
function, their associated early-warning detectors would almost inevitably
also be destroyed. To be sure, the likelihood of such attacks could be reduced
by choosing host satellites that might not otherwise be targets (ad esempio
weather or commercial noncommunication satellites), and the consequences
of such attacks would be mitigated by having multiple detectors in orbit.
Nonetheless, a dispersed system could not eliminate the risks associated with
incidental attacks.
Separately, deploying a dispersed system in addition to more capable dedi-
cated early-warning satellites, such as SBIRS, might increase an adversary’s in-
centives to attack the dedicated satellites (by reducing the escalation risks of
doing so), and would be more expensive than ªelding either system alone.120
By contrast, deploying a dispersed system instead of dedicated satellites
would lower the effectiveness of missile defenses.
Reducing an adversary’s incentives to launch incidental attacks against
space-based communication assets would be more difªcult. Although a sys-
tem that was capable of transmitting data only at low rates would be some-
what more useful for nuclear than nonnuclear operations, there would be no
obvious way of demonstrating to adversaries that such a limitation was real
118. Eugene Hecht, Optics, 5th ed. (Boston: Pearson, 2017), P. 493.
119. Acton, “Command and Control in the Nuclear Posture Review.”
120. If a dispersed system could be kept secret, its existence could not incentivize attacks against
dedicated satellites. Under this approach, the United States would obviously not attempt to con-
vince potential adversaries that the dispersed system was ineffective for any mission other than
detecting missile launches.
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Escalation through Entanglement 97
and permanent. Invece, risk-reduction efforts could focus on mitigating the
consequences of incidental attacks against space-based communication assets
by enhancing their resilience. One approach would be to create an upgraded
version of AFSATCOM by hosting small communication transponders for nu-
clear operations on tens of satellites used for other purposes (Anche se, Ancora,
trade-offs similar to those associated with a dispersed early-warning system
would arise).
Conclusione
As U.S.-Chinese and U.S.-Russian tensions have increased, albeit nonmono-
tonically, since the mid-2000s, warnings about the escalation risks that are in-
herent to the way that the United States would likely approach a great-power
conºict have grown louder.121 This focus on American doctrine and technol-
ogy, Tuttavia, has largely obscured another danger: the emerging Chinese and
Russian ways of ªghting wars are inherently escalatory too.
Both China and Russia, like the United States, seek to threaten potential ad-
versaries’ C3I assets and are improving their capabilities to do so. Because
many enabling assets are dual use, Tuttavia, attacks against them could, in the
event of a conºict, degrade the target’s nuclear C3I system just as a nuclear
war was becoming all too imaginable. Crisis instability is one potential conse-
quence. Infatti, its risks are more serious than generally understood because
C3I assets that are space-based or distant from potential theaters of conºict
could be subject to incidental kinetic attack or cyber interference. Addi-
tionally, C3I vulnerability could generate two other escalation pressures—
misinterpreted warning and the damage-limitation window—that have not
been previously discussed. Attacks against ISR assets, which would be likely
in a major conºict, would exacerbate the risks by complicating the task of as-
sessing an attacker’s intent and by raising concerns about follow-on attacks
against dual-use early-warning and communication assets.
In the future, the extent of entanglement—and hence the magnitude of these
escalation risks—is likely to increase. Early-warning capabilities are likely to
become more entangled with nonnuclear weapons as China and Russia mod-
ernize early-warning systems, and especially if one of them or the United
States deploys nonnuclear SLBMs, ICBMs, or long-range hypersonic boost-
121. This literature has a broader focus than the vulnerability of nuclear forces and C3I assets. Vedere,
Per esempio, Keir A. Lieber and Daryl G. Press, “The Nukes We Need: Preserving the American
Deterrent,” Foreign Affairs, Vol. 88, No. 6 (November/December 2009), P. 43.
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International Security 43:1 98
glide weapons, which could be monitored in ºight with capabilities primarily
designed to detect a nuclear strike. Other nuclear C3I capabilities could also
become more deeply integrated into nonnuclear missions. Because dual-use
weapon-delivery systems may become more common, Per esempio, the over-
lap between nuclear and nonnuclear enabling capabilities (such as communi-
cation and mission planning systems) is also likely to increase.
Nonnuclear threats to dual-use C3I capabilities are also likely to become
more serious. Per esempio, as part of U.S. efforts to enable forces to “take ad-
vantage of freedom of action in one domain to . . . challenge an adversary in
another,” the United States could develop or enhance ASAT capabilities—
including kinetic ones, perhaps—for targeting dual-use Chinese and Russian
communication and ISR satellites.122 Meanwhile, if Beijing or Moscow devel-
ops long-range nonnuclear hypersonic boost-glide weapons, it may be able to
threaten the uplinks and downlinks for U.S. satellites across the world, includ-
ing in the continental United States—potentially endangering the functionality
of multiple dual-use U.S. C3I systems.
If these risks are to be ameliorated—or, at the very least, if their rate of in-
crease is to be stemmed—China, Russia, and the United States will ªrst have
to conclude that the risks of entanglement outweigh the beneªts. If one or
more of them reaches that conclusion then, for the time being, unilateral risk-
reduction measures (including the use of declaratory policy to underscore the
risks of attacking dual-use C3I assets and the development of more resilient
C3I systems) offer the most promising way forward. Establishing risk-
reduction teams would help institutionalize and inform these efforts and, per-
haps most importantly, raise awareness of the risks within governments and
militaries, thus helping to mitigate them.
Over the longer term, cooperative risk-reduction measures could be adopted
to further mitigate the risks, particularly the threat to dual-use C3I capabilities.
Although there is little prospect of such measures being negotiated today, IL
level of interest in them could rise in the future—because of a thaw in political
relations, perhaps, or a dangerous crisis that shocked political leaders into ac-
zione. States could, Per esempio, commit not to engage in cyber interference
with one another’s nuclear C3I systems.123 They could also agree to prohibit
122. Air-Sea Battle Ofªce, “Air-Sea Battle," 4. See also Biddle and Oelrich, “Future Warfare in the
Western Paciªc,” pp. 44–45; and Christensen, “The Meaning of the Nuclear Evolution,” p. 472.
123. Richard J. Danzig, “Surviving on a Diet of Poisoned Fruit: Reducing the National Security
Risks of America’s Cyber Dependencies” (Washington, D.C.: Center for a New American Secu-
rity, Luglio 2014), pag. 24–27, https://s3.amazonaws.com/ªles.cnas.org/documents/CNAS_Poisoned
Fruit_Danzig.pdf.
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Escalation through Entanglement 99
the testing of ASAT weapons capable of threatening objects in geostationary
orbit (where the most important space-based nuclear C3I assets are located).124
Such prohibitions could prove effective if each participant assessed that the
costs of violating the agreement—most obviously, the possibility that potential
adversaries would engage in reciprocal violations—outweighed the disadvan-
tages of compliance.
To make such prohibitions workable, signiªcant technical challenges would
need to be overcome. How would a prohibition against interfering with nu-
clear C3I systems be deªned? What command-and-control systems would be
covered given that so many of them are dual use? Allo stesso modo, what kind of
weapons—precisely—would be included in a ban on testing ASAT weapons
capable of reaching geostationary orbit? While challenging to answer, these
questions are not necessarily unanswerable. Infatti, the process of designing
unilateral risk-reduction measures might stimulate and facilitate thinking
about cooperative risk reduction by creating enhanced understanding of the
risks associated with entanglement as well as the expertise to manage them. In
Da questa parte, by embarking on unilateral risk-reduction processes now, China,
Russia, and the United States could better position themselves to take advan-
tage of any political opportunities for negotiations on cooperative measures
that might arise in the future.
124. Arbatov, Dvorkin, and Topychkanov, “Entanglement as a New Security Threat,” pp. 40–41.
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