Keywords

1 Introduction

Relations between Moscow and Beijing have warmed steadily since the late Soviet period. This trend began with moves toward Sino-Soviet normalization, proceeded in stages following the Soviet collapse, and gained momentum in recent years, when the China-Russia alignment became particularly close. Nuclear issues have played an important role in the relationship throughout this period, acting as a source of both potential discord and emergent cooperation. The decline of Russian military power in the post-Soviet period and the concurrent growth of China’s military capabilities aroused anxiety among Russian leaders and strengthened their determination to maintain nuclear deterrence of China. At the same time, facing preponderant US power in the wake of the Soviet collapse, both countries opposed the development of US military capabilities that could have undermined their own capacity for nuclear deterrence of the United States. China and Russia cooperated in opposing US plans that potentially threatened their second-strike capabilities, including the deployment of national or theater missile defense systems and the development of high-precision conventional weapons (Medeiros & Chase, 2017, July, pp. 6–7; Rumer, 2017, July, p. 24). As the China-Russia relationship grew steadily closer, sources of discord on nuclear issues faded to the background, while cooperation became increasingly prominent.

Beyond shared interests in the preservation of nuclear deterrence of the United States, China and Russia also strengthened their bilateral defense cooperation. The main features of this cooperation, including Russian arms sales to China, the conduct of joint military and naval exercises, and defense consultations, grew steadily over time and have expanded notably in recent years, especially since the onset of the Ukraine crisis (Kashin, 2018, August). China-Russia defense cooperation focuses on conventional weapons. Russian arms sales to China have made significant contributions to China’s conventional military capabilities, including its capacity for anti-access/area denial (A2/AD), but they exclude nuclear weapons (Weitz, 2017, July, p. 30). Nor, at least according to publicly available evidence, have the two countries conducted joint research and development in nuclear, hypersonic, or other strategic offensive capabilities. The two countries’ joint military and naval exercises have grown in sophistication, but they have focused primarily on scenarios of military conflict at the conventional level, below the threshold of nuclear escalation.

In recent years, however, China and Russia have strengthened cooperation on issues of broader strategic significance. In 2016 and 2017, they held joint missile defense exercises in the form of computer simulations. In 2019, Russian President Vladimir Putin revealed that Russia was helping China to build a missile attack early warning system. China and Russia continue to oppose US missile defense systems. Both countries have declared their opposition to US deployment of land-based intermediate-range ballistic missiles in Asia following the demise of the Intermediate-Range Nuclear Forces (INF) Treaty (Blank, 2020b, p. 266). The two countries stand together in criticizing US development of high-precision weapons, opposing the weaponization of space even while testing their own anti-satellite weapons, and advocating positions on cyber issues that emphasize national sovereignty (Medeiros & Chase, 2017, July, p. 7).

Such cooperation and expressions of shared views demonstrate a common desire to place constraints on the exercise of US power. This desire, though hardly the only driver of the China-Russia relationship, has been an important stimulus for the two countries’ growing cooperation. The recent strengthening of China-Russia relations has occurred amid downturns in both countries’ relations with the United States (Ellings & Sutter, 2018). Convergent views on a series of issues, including shared opposition to a US-dominated international system and to the principle of an international order based on liberal political values, provide a firm foundation for the relationship (Rozman, 2014). This situation has important implications for the global balance of nuclear forces and for efforts to ensure strategic stability. Cooperation by China and Russia to strengthen their respective nuclear deterrents is already an important factor in international security and could grow in importance over time. This chapter assesses actual China-Russia cooperation in nuclear deterrence to date, as well as the potential for further collaboration in this area.

2 Nuclear Weapons and Great Power Competition

In recent years, US foreign policy has increasingly focused on great power competition with China and Russia, including the nuclear dimensions of this competition. The 2018 Nuclear Posture Review assessed the challenges posed by both countries’ growing nuclear arsenals. This document argued that Russia’s modernization and expansion of its nuclear arsenal, including its stockpile of nonstrategic nuclear weapons, reflected Russia’s belief that it could use the threat or actual first use of nuclear weapons in order to “de-escalate” an armed conflict on favorable terms. It also argued that despite no change in China’s official doctrine, including its commitment to no first use of nuclear weapons, China’s nuclear modernization and lack of transparency raised questions about the country’s future intentions (Department of Defense, 2018, February, pp. 8–11). In May 2019, Lt. Gen. Robert P. Ashley, Jr., director of the Defense Intelligence Agency, predicted that both Russia and China would expand their nuclear arsenals significantly, with China most likely at least doubling the size of its nuclear stockpile (Ashley, 2019, May 9). The Department of Defense’s 2020 report on China’s military power echoed this assessment, projecting that China over the following decade would at least double the size of its nuclear warhead stockpile, which the report estimated to be in the low 200s at the time of publication (Department of Defense, 2020, pp. ix, 85, 87). The 2021 report anticipated an even more rapid pace of development, projecting that China could have 700 deliverable nuclear warheads by 2027 and 1000 warheads by 2030 (Department of Defense, 2021, pp. viii, 90, 92). The communiqué that NATO heads of state issued at the conclusion of their summit in June 2021 criticized both Russia and China for their nuclear buildups (North Atlantic Treaty Organization, 2021, June 14).

For its part, the United States plans a program of nuclear force modernization over the next two decades to upgrade nuclear weapons and delivery systems. Some US delivery systems, including Minuteman ICBMs, have been in service for decades. Russia and China both argue that their own nuclear upgrades are necessary because US plans, including nuclear force modernization, missile defense programs, and the development of high-precision conventional weapons, threaten their nuclear deterrents. The United States maintains a traditional arms control relationship with Russia, as reaffirmed by the renewal of the New Strategic Arms Reduction Treaty (New START) in the early days of President Joe Biden’s administration. This treaty limits both countries to 1550 deployed nuclear warheads and bombs. China has declined to enter international arms control negotiations until the United States and Russia reduce their total number of warheads to levels approaching the size of China’s arsenal, which according to some estimates may hold up to 350 warheads (Kristensen & Korda, 2020a, pp. 443–444).

Putin’s most recent nuclear policy guidelines, published in 2020, declare that Russia views nuclear weapons exclusively as a means of deterrence. The guidelines list several conditions under which Russia would use nuclear weapons, including confirmation of an incoming ballistic missile attack against Russia or its allies, the use of nuclear weapons or other weapons of mass destruction against Russia or its allies, an attack on critical governmental or military sites that would undermine Russia’s ability to respond with nuclear weapons, or an attack on Russia with conventional weapons that would put the state’s existence in jeopardy (President of the Russian Federation, 2020, June 8). Many outside analysts argue, however, that such principles are not congruent with Russia’s nuclear force structure, capabilities, and exercises (Johnson, 2021). In addition to the “escalate to de-escalate” concept suggested by the Nuclear Posture Review, other analysts argue that Russia’s actual aim is to “escalate to win” (Kristensen & Korda, 2020b, p. 105) or to maintain escalation dominance at all stages of a conflict (Blank, 2020a, p. 231).

Russia’s recent nuclear force modernization and deployments reinforce such concerns. In addition to modernizing all three legs of its nuclear triad, it has developed new intercontinental-range systems such as a hypersonic glide vehicle, a nuclear-armed, nuclear-powered cruise missile, and a nuclear-armed, nuclear-powered, undersea autonomous torpedo. Russia has also established superiority in nonstrategic, dual-capable systems that can be armed with either nuclear or conventional warheads. These include the SSC-8/9 M729, a ground-based cruise missile that the United States and NATO alleged was in violation of the INF Treaty. Russia holds an estimated stockpile of more than 4000 total warheads (Kristensen & Korda, 2020b, p. 102).

China’s most recent defense white paper, which was published in 2019, reaffirms the country’s policy of no first use (NFU) of nuclear weapons. This document adds that China refrains from engaging in nuclear arms races with other countries and maintains nuclear capabilities at the minimum level required for national security. The goal of the country’s nuclear arsenal, the document states, is to deter other countries from using or threatening to use nuclear weapons against China (State Council Information Office, 2019, July).

China announced its NFU doctrine following its first successful nuclear test in 1964. For several decades thereafter, the country sought to maintain a minimum nuclear deterrent. By the early 2000s, China most likely possessed only a few dozen nuclear weapons that could strike the United States, all of which were silo-based, leaving them vulnerable. Since then, however, China has made significant strides in the modernization of its nuclear forces. It has deployed road-mobile intercontinental ballistic missiles (ICBMs), equipped some of its strategic missiles with multiple independently targetable re-entry vehicles (MIRVs), and deployed the PLA Navy’s first viable ballistic missile submarines (SSBNs). China has also increased the size of its nuclear arsenal, though at least until recently it still appeared to maintain a “lean and effective” nuclear force rather than striving for numerical parity with the United States and Russia (Chase & Carlson, 2019, October, pp. 3–5). As noted above, however, US officials harbor concerns that China plans a major buildup of nuclear forces, which potentially could lead to changes in doctrine. In 2021, satellite images showed that China was constructing approximately 300 missile silos, adding to suspicions about China’s intentions for its nuclear arsenal (Korda & Kristensen, 2021, November 2; Warrick, 2021, June 30).

Beyond US apprehensions about Russia and China individually, cooperation by the two countries in nuclear deterrence is an additional source of concern. As this chapter details, the history of relations between Moscow and Beijing on nuclear issues is long and complex, at times mixing elements of cooperation and wariness. Their shared desire to maintain credible deterrence of the United States, however, now provides a basis for continued and expanded cooperation in this area. The next section offers a framework for analyzing the evolution of nuclear relations between Moscow and Beijing.

3 Evolution of Moscow-Beijing Nuclear Relations

Since China’s acquisition of nuclear weapons in 1964, several years after the beginning of the Sino-Soviet split, relations between Moscow and Beijing in the nuclear sphere have passed through several phases. According to a typology proposed by Nikita Perfilyev (2018a, December 4; 2018b, December 12), the nuclear relationship between the Soviet Union and China was explicitly adversarial from 1964 to 1985 before turning implicitly adversarial from 1986 to 2013, including periods of transition (1986–1993) and consolidation (1993–2013). As a result of the strengthened China-Russia relationship following the onset of the Ukraine crisis, the implicitly adversarial elements faded. This marked the beginning of a new phase featuring implicitly cooperative relations directed against the United States and its allies. The formation of an explicitly cooperative relationship similar to that between the United States and Britain now also loomed as a possibility.

During the 1960s, the Sino-Soviet split underwent transformation from an ideological conflict into a power struggle between two enemy states. Several events in 1964 exacerbated Sino-Soviet tensions. In addition to China’s nuclear test, these events included China’s announcement that it supported Japan’s demand for the return of the Kuril Islands and Mao’s assertion that a vast stretch of Soviet territory had been seized from China by tsarist imperialism. In response, the Soviet Union began a major military buildup along the Chinese border. China’s Cultural Revolution, which began in 1966, had a strong anti-Soviet tenor, and the Soviet buildup accelerated. By 1968, the size of Soviet forces along the border had doubled since 1961.

The growing tensions led to armed border clashes in 1969. On March 2, Chinese forces attacked Damansky (Zhenbao) Island in the Ussuri River. On March 15, the Soviets counterattacked and reclaimed the island. These events caused a shift in Soviet thinking, as Soviet leaders urgently upgraded their estimate of the threat. The Soviets adopted a policy of containment and intimidation toward China, accelerating the military build-up. Later that summer, following further border clashes in Xinjiang, the Soviet Union probed the United States to learn how it would react in the event of an attack, possibly even a nuclear strike, on China’s nuclear facilities, to which the United States responded negatively. The border clashes and the ensuing tension throughout 1969 appear to have been a major factor in Mao’s decision to pursue rapprochement with the United States. In subsequent years, China and the Soviet Union continued to eye each other warily. China deployed the DF-4 missile along the Soviet border in the mid-1970s. The Soviet Union, in turn, explored the possibility of laying nuclear mines along the border in order to stop a full-scale Chinese invasion should deterrence fail (Perfilyev, 2018a, December 4; 2018b, December 12).

The Soviet Union soon attempted diplomatic outreach to China, however. In a 1982 speech, Soviet leader Leonid Brezhnev called for improved relations. Later that same year, irritated by continued US support for Taiwan, Chinese leader Deng Xiaoping announced that China would pursue an independent line in foreign policy. However, the Soviet Union remained unwilling to make the concrete concessions that could have improved Sino-Soviet relations. It was only during Mikhail Gorbachev’s tenure that the Soviet Union took the necessary steps to mend the rift, ending the explicitly adversarial phase of nuclear relations.

4 Nuclear Issues from Gorbachev to the Ukraine Crisis

Despite the end of explicitly adversarial relations, the nuclear relationship between Moscow and Beijing retained its adversarial elements, though in a softer, implicitly adversarial form. The official shelving of nuclear issues in the China-Russia relationship meant that the two countries no longer officially recognized the existence of nuclear deterrence in their bilateral relations. Nevertheless, the security of the Russian Far East and Siberia still depended on nuclear deterrence. Thus, in the “great strategic triangle” that emerged during the post-Soviet era, the US-Russia relationship was characterized by symmetric deterrence, the US-China relationship by asymmetric deterrence, and the Russia-China relationship by latent deterrence (Arbatov & Dvorkin, 2013, pp. 12, 14).

4.1 Establishing the New Relationship

From 1985 to 1993, the new implicitly adversarial relationship passed through a period of transition. Gorbachev achieved normalization of relations in 1989 by satisfying China’s three demands, namely, by ending the Soviet military presence in Afghanistan, securing the withdrawal of Vietnamese military forces from Cambodia, and ending the Soviet military buildup along China’s border. The latter step included the removal of 171 SS-20s and 256 other missiles from regions east of the Urals under the terms of the INF Treaty that the United States and the Soviet Union signed in 1987, with China’s encouragement (Charap, 2019, April 9, p. 4; Perfilyev, 2018a, December 4; 2018b, December 12).

Following the breakup of the Soviet Union, Russian President Boris Yeltsin and his administration sought to integrate the new Russia into the West and initially scorned relations with China. During this period, Russia’s security policy reflected these priorities. Thus, its first post-Soviet military doctrine, which was promulgated in November 1993, abandoned the pledge of no first use of nuclear weapons that Brezhnev had made in 1982. Many analysts viewed this change as an effort to establish nuclear deterrence against potential aggressors, especially China (Schmemann, 1993, November 4; Garnett, 2000, pp. 8–9). Yeltsin soon reconsidered his approach and sought to strengthen ties with China, an effort made manifest in the two countries’ nuclear relationship. During Chinese President Jiang Zemin’s visit to Moscow in September 1994, when China and Russia declared the formation of a “constructive partnership,” the two countries pledged no first use of nuclear weapons in their bilateral relations. They also agreed not to target their nuclear warheads at each other (Garnett, 2000, pp. 8–9; Garnett, 2001, pp. 45–46).

These agreements signaled the end of transition and the beginning of the period of consolidation in the implicitly adversarial relationship. China and Russia later enshrined these pledges in the Treaty of Good-Neighborliness, Friendship, and Cooperation, which they signed in 2001. In the intervening years, the two countries formed a “strategic partnership” in 1996, opposed the 1999 US bombing campaign against Yugoslavia, and coordinated their opposition to US plans for theater and national missile defense.

4.2 Joint Opposition to US Ballistic Missile Defense

Both China and Russia opposed US ballistic missile defense plans, which gained momentum in the late 1990s, because they feared that such systems could threaten the effectiveness of their respective nuclear deterrents and entrench US military dominance. For both China and Russia, nuclear ballistic missile forces helped to offset the US advantage in overall military power. In a potential direct conflict, their possession of ballistic missiles introduced the risk of nuclear escalation, which could force the United States to exercise restraint in deploying conventional military forces. The deployment of reliable missile defense systems by the United States could reduce the risk of nuclear escalation by its adversaries. In this case, in the view of China and Russia, the United States might conclude that it could keep potential military clashes at the conventional level, where it held considerable advantages that were likely to endure, and avoid nuclear escalation (Goldstein, 2005, p. 140). In addition to their opposition to national ballistic missile defense, China and Russia also agreed that theater missile defense systems, which were not prohibited by the ABM Treaty, should not be deployed in ways that harmed other countries’ security. In particular, they agreed that the deployment of a theater missile defense system covering Taiwan was unacceptable. Between 1999 and 2001, China and Russia introduced three resolutions in the UN General Assembly calling for the ABM Treaty’s preservation, all of which received approval.

China and Russia maintained their united diplomatic front on ballistic missile defense during this period despite some differences in their national interests. Russia’s nuclear arsenal was much larger and more sophisticated than China’s. Therefore, although Russia opposed US efforts to revise the ABM Treaty or to withdraw from it altogether, Russian leaders remained confident that a limited US national ballistic missile defense system, designed to protect the country against accidental launches or limited strikes by countries such as Iran or North Korea, would be unlikely to pose a serious threat to the Russian nuclear deterrent. China, by contrast, feared that even a limited US national missile defense system could threaten the effectiveness and credibility of its nuclear deterrent (Goldstein, 2005, p. 140). China was also much more concerned than was Russia about theater missile defense systems, especially one that would cover Taiwan (Lo, 2008, pp. 50–51).

China’s overall concerns about US missile defense were greater than Russia’s (Goldstein, 2005, p. 141). This divergence of interests became clear later, when Putin mounted little resistance to President George W. Bush’s December 2001 decision to withdraw from the ABM Treaty. China had hoped to maintain a united front with Russia on this issue, but Putin bowed to the inevitable during a period of warming US-Russia relations following the terrorist attacks of September 11, 2001. Putin acknowledged that the United States had the right to withdraw from the treaty, but he expressed confidence that Russia maintained the ability to overcome any potential missile defense system. In the view of Chinese leaders and analysts, Putin effectively gave tacit approval to the US withdrawal from the treaty. This was disappointing to Chinese leaders. The Chinese government, in contrast to Putin’s mild response, strongly condemned the US decision. In later years, China and Russia continued to oppose US missile defense plans, including the deployment of the Thermal High-Altitude Area Defense (THAAD) system in South Korea. Their diverging responses to the US withdrawal from the ABM Treaty, however, revealed that their positions on nuclear issues were not fully in harmony. This soon became apparent on a range of other nuclear issues as well.

4.3 Areas of Discord

Russia’s relations with the West deteriorated throughout the first decade of the twenty-first century, providing an impetus for closer relations with China. Nevertheless, Russia maintained largely unspoken concerns about China’s growing military capabilities. Russia faced an increasingly unfavorable military balance in Asia resulting from increases in the capabilities of the People’s Liberation Army (PLA), particularly its conventional forces based in northern China. Despite the bilateral pledge of no first use of nuclear weapons against each other, the 2010 Military Doctrine of the Russian Federation hinted that Russia’s ability to deter a potential Chinese invasion ultimately depended on the country’s nuclear forces, including both strategic and tactical nuclear weapons (Arbatov & Dvorkin, 2013, p. 12; Kipp, 2011). This deterrent was partly based on the threat to use tactical nuclear weapons in the early stages of a conflict (Kashin, 2013, May 1).

Russian concerns about China’s growing conventional military power, including its large arsenal of intermediate- and shorter-range missiles, may have been an important factor in its violation of the INF Treaty. In 2007, then-Russian Defense Minister Sergei Ivanov criticized the treaty publicly: “The gravest mistake was the decision to scrap a whole class of missile weapons—medium-range ballistic missiles. Only Russia and the United States do not have the right to have such weapons, although they would be quite useful for us” (Kühn & Péczeli, 2017, pp. 70–71). Putin also repeatedly complained that several of Russia’s neighbors possessed missiles of this range (Charap, 2019, April 9, p. 4).

Russian leaders also expressed their desire for China to participate in future arms control negotiations. Following the signing of New START in 2009, Russian officials declared their reluctance to participate in future arms control negotiations without China’s participation. They also called for Britain and France to participate. China insisted that it would not participate in arms control negotiations until the United States and Russia first reduced their nuclear arsenals to levels that were close to China’s, even as China maintained secrecy about its total number of warheads (Arbatov & Dvorkin, 2013).

Russia’s discussions with NATO in 2010 about possible cooperative arrangements in missile defense were another potential source of tension in Russia’s relations with China. Although China raised no public objections to these discussions, some Russian experts believed that China must have been concerned. In their view, China might have perceived a NATO-Russia cooperative missile defense system as an “anti-Chinese conspiracy” that would have damaged China-Russia relations and necessitated a large buildup of Chinese nuclear forces (Arbatov & Dvorkin, 2013, p. 20). These talks raised the possibility that Russia might be obligated to shoot down Chinese missiles aimed at Western countries, an arrangement to which China naturally would have objected strenuously (Alexei Arbatov, interview with author, Moscow, June 2, 2016.)

Some of Russia’s military exercises during this period appeared to reflect its concerns about China. In 2009, China conducted military exercises (Stride-2009) simulating a large-scale land invasion, which looked to some Russian experts like a dress rehearsal for an attack on Russia (Khramchikhin, 2010, February 17; Khramchikhin, 2013, pp. 65–66). The following summer, the Russian military conducted the quadrennial Vostok (East) military exercises in the Siberian and Far Eastern military districts. Russian military officials insisted that the exercises were not aimed at “any one country or bloc.” However, given the exercises’ geographical setting, participating forces, and simulated operations, outside experts argued that the true purpose was to test the Russian military’s ability to defend the country’s eastern regions against a potential Chinese invasion (McDermott, 2010a, July 6; Kipp, 2010, July 12). On the final day of the exercises, the Russian military appeared to simulate a tactical nuclear strike against enemy forces. The exercise may have sought to determine how long Russian conventional forces could withstand an invasion by the PLA before resorting to the use of nuclear weapons (McDermott, 2010b, July 13). Three years later, when five Chinese warships sailed through the Sea of Okhotsk, Russia called snap military exercises in the region. Thus, on the eve of the Ukraine crisis, the latent deterrence in China-Russia nuclear relations remained in force.

5 Nuclear Cooperation Since the Ukraine Crisis

The strengthening of China-Russia relations following the onset of the Ukraine crisis and the resulting imposition of Western sanctions on Russia caused the implicitly adversarial elements of the nuclear relationship to fade. Although Russia’s defense against a potential Chinese invasion continued to rely on nuclear deterrence, the improvement of the China-Russia relationship meant that Russia no longer viewed China as a threat. China’s participation in Russia’s Vostok-2018 domestic military exercises clarified this shift. As mentioned above, Russia appeared to simulate a tactical nuclear strike against invading Chinese forces during the 2010 version of these quadrennial exercises. Four years later, despite the beginning of intensified Russian diplomatic outreach to China, the Vostok-2014 exercises were oriented toward the defense of the Russian Far East against an invasion by a state actor, a role that could only be played in the real world by China (McDermott, 2014a, September 23; McDermott, 2014b, September 30). China’s participation in Vostok-2018, which marked the first time that China had participated in domestic Russian military exercises, thus represented a stark shift in Russia’s outlook (Carlson, 2018, November). By inviting China to participate, Russia conveyed a clear message that it no longer viewed China as a military threat to its eastern regions (Gabuev, 2018, September 11). Following the onset of the Ukraine crisis, Russia also approved sales of the S-400 air and missile defense system and Su-35 fighter jets to China.

As the adversarial elements faded, the relationship entered a new period of implicit cooperation against the United States and its allies. The improvement in China-Russia relations led to bilateral cooperation on a range of issues connected to nuclear weapons and strategic stability. Geographically, Northeast Asia became a focal point. Indicative of the warming relationship was China’s 2017 deployment of road-mobile DF-4 ICBMs in its northeastern province of Heilongjiang, near the border with Russia. This deployment positioned these missiles in such a way that they could strike the entire continental United States. It also put them within range of Russian missiles, but this was not a major concern for Chinese leaders in view of their strong relationship with Russia (Perfilyev, 2018a, December 4; 2018b, December 12).

5.1 Continued Opposition to US Missile Defense

In the new period, China and Russia continued their long-standing opposition to US missile defense systems. They cooperated in opposing the deployment of THAAD on South Korean territory, which the United States argued was necessary in order to defend South Korea and US military bases in Asia from North Korean missile strikes. China and Russia were united on this issue despite differences in their interests resulting from contrasts in their nuclear arsenals. China argued that this system posed a direct threat to its nuclear deterrent, noting that the monitoring range of the system’s X-band radar reached far beyond the Korean Peninsula and deep into Chinese territory. Russian leaders knew that their country’s nuclear arsenal remained large enough to overwhelm THAAD or any other prospective theater or national missile defense system, but they professed concern that the United States intended to establish a global missile defense system that could eventually threaten the effectiveness and credibility of Russia’s nuclear deterrent (Toloraya, 2019, February 19; Weitz, 2018, p. 85).

In June 2016, China and Russia issued a joint declaration on global strategic stability in which they expressed their shared opposition to THAAD, as well as to US deployment of Aegis Ashore missile defense systems, development of high-precision conventional weapons as envisioned in the Prompt Global Strike program, and weaponization of space (Xi & Putin, 2016, July 8). Efforts to prevent the deployment of THAAD were unsuccessful, as the United States began to install the system in South Korea during the spring of 2017. Opposition to US missile defense continues to be a major emphasis for China and Russia, however. The two countries responded harshly to the Trump administration’s 2019 Missile Defense Review, which called for the augmentation of defenses against regional ballistic, cruise, and hypersonic missile threats no matter the source, effectively linking US missile defense plans to Russia and China for the first time (Reif, 2019, March).

5.2 Coordination in Northeast Asia

Much recent China-Russia cooperation on defense and nuclear deterrence has a distinct geographical focus on Northeast Asia. This includes opposition to the deployment of THAAD in South Korea, cooperation in addressing the North Korean nuclear crisis, joint air patrols in Northeast Asia, and efforts to limit force deployments by the United States and its allies in the region that China and Russia perceive as threatening. Although the two countries have no treaty obligations to provide each other with mutual support in scenarios of armed conflict, their close defense cooperation raises the possibility of joint operations in a military contingency. A potential military conflict on the Korean Peninsula that could involve Russian and Chinese nuclear weapons is especially relevant in this context (Blank, 2020b, pp. 267–268).

In recent years, China and Russia have closely coordinated their diplomacy toward the Korean Peninsula (Carlson, 2019). Both countries supported the denuclearization of the peninsula in principle, but they also viewed North Korea’s nuclear program as the ultimate deterrent against US efforts at regime change. China and Russia have a shared desire to weaken the US strategic position in Northeast Asia, including the US-South Korea alliance. The existing regional security architecture, especially the US military presence in the region, offers China and Russia a strong incentive to protect the regime in Pyongyang (Lukin, 2017, October 25, p. 3).

China and Russia may also have discussed possible military contingencies in the region. No publicly available evidence suggests that the Chinese and Russian militaries have developed joint operational plans, but some Russian analysts suggest that the Korean Peninsula and Central Asia are the two regions most likely to be included in any such plans (Gabuev, 2018, September 11). Russia and China may have intended to use the Vostok-2018 exercises as a display of their military power in Northeast Asia in anticipation of the possible outbreak of armed conflict on the Korean Peninsula (Goldstein, 2018, September 5). In such an armed conflict, China might wish to secure Russia’s military support. Russia’s recent combat experience and especially its nuclear arsenal could prove valuable, increasing the likelihood that China could achieve a favorable outcome (Lukin, 2017, October 25, p. 3).

Less than 1 year after the Vostok-2018 exercises, China and Russia offered a further sign of their intensified bilateral defense cooperation by conducting their first joint air patrol (Kofman, 2019a, July 26); Blank, 2019). Northeast Asia was the scene of the patrol, which occurred in July 2019 and featured two Tu-95MS strategic bombers and a Beriev A-50 airborne-warning and control aircraft on the Russian side and two H-6 K long-range bombers and a KJ-2000 battlespace management aircraft on the Chinese side. The air patrol featured no explicitly nuclear component. The H-6 K does not play a prominent role in China’s nuclear deterrent because, although it carries high-precision cruise missiles, it has a limited range and is incapable of in-flight refueling. However, it makes an important contribution to China’s A2/AD capability, enabling the PLA to launch massive nonnuclear missile strikes against US targets in the region. Russian strategic bombers such as the ones that participated in the air patrol, which have long been the crucial element of the airborne leg of Russia’s nuclear triad, are now also capable of launching high-precision nonnuclear weapons. Because Russia’s naval power in the Pacific is weak, long-range aviation is the country’s primary means of power projection in the region (Kashin, 2019, July 30).

During the joint air patrol, the Russian and Chinese aircraft crossed into the air defense identification zones (ADIZ) of both South Korea and Japan in the East China Sea, prompting both countries to scramble fighter jets in response. The A-50 also flew close to Dokdo/Takeshima island, which is controlled by South Korea but also claimed by Japan, and entered what South Korea considers to be its airspace. The South Korean air force fired warning shots at the A-50, an action that drew criticism from Japan’s foreign minister, who declared that protecting the airspace around the disputed island was Japan’s prerogative. The location of the air patrol suggested that it may have been intended, at least in part, to drive a wedge between South Korea and Japan. This is one of China’s primary objectives in the region, and Russia’s participation suggested its willingness to support this effort. For Russia, the joint air patrol was an opportunity to show that it was still a significant power in Asia and also that it was willing to take risks for the sake of its relationship with China (Kofman, 2019a, July 26). A second, similar joint air patrol occurred in December 2020.

China and Russia were undoubtedly pleased with Japan’s June 2020 decision, ostensibly for cost and environmental reasons, not to host the US Aegis Ashore missile defense complex. This decision could lead China and Russia to conclude that Japan is susceptible to pressure. If, for example, the United States attempted to deploy land-based intermediate-range missiles on the territory of its Asian allies following the demise of the INF Treaty, China and Russia might believe that they could pressure Japan to refuse its consent to such plans (Blank, 2020b, 258–259). Following recent upgrades to Japanese military forces, including the purchase of F-35 fighter jets from the United States, Russia strengthened its own military presence in Northeast Asia, deploying forces that are designed to counter the United States and Japan, not China. Russia deployed the S-300 V4, an advanced air defense system, on one of the four disputed islands that Russia controls but Japan claims (Simes, 2020, December 16). Cooperation between China and Russia in a potential armed conflict in Northeast Asia, including combined efforts to ensure nuclear deterrence of the United States, is a possibility that US defense planners must consider.

5.3 Missile Defense and Early Warning

China and Russia held joint missile defense exercises in May 2016 and December 2017 in the form of computer simulations. In these exercises, the two countries employed their respective surface-to-air missile (SAM) systems, the Chinese HQ-9 and the Russian S-300/400 series, to establish a joint area for air and missile defense (Kashin, 2018, August, p. 20). These exercises required the two sides to share information in sensitive areas such as missile launches, warning systems, and ballistic missile defense. The willingness of China and Russia to share such information and to display their C4ISR (Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance) systems suggested a desire by both countries to improve their capacities for interoperability and joint command and control (Blank, 2020b, pp. 258–259).

In October 2019, Putin announced that Russia was assisting China in the construction of a missile attack early warning system. At present, the United States and Russia are the only two countries that possess early warning systems. China’s acquisition of such a system could contribute to global strategic stability by reducing uncertainty in a crisis (Kashin, 2021, February 21; Kofman, 2019b, November 29). However, it could also prompt China to increase the alert levels of its nuclear arsenal and possibly adopt a doctrine of “launch on warning.” Moreover, it could lead China to deploy ballistic missile defense systems and an integrated network of anti-satellite capabilities (Wishnick, 2020, March 1; Blank, 2020b, p. 260). From the perspective of China-Russia cooperation, the main significance of the deal lies in the high level of trust that it demonstrates between the two countries (Kashin, 2021, February 21; Gorenburg, 2020, April). It marks a notable shift into cooperation in strategic capabilities (Kofman, 2019b, November 29). It could conceivably lead to the development of an integrated China-Russia missile defense system, though the two countries have stated no such intention (Kashin, 2021, February 21).

5.4 Post-INF Cooperation

The demise of the INF Treaty was a potential source of tension in China-Russia relations. In August 2019, the United States withdrew from the treaty, which prohibited land-based missiles with ranges of between 500 and 5500 kilometers, on the grounds of Russia’s violation. Russia insisted that its deployment of the SSC-8/9 M729 was in compliance with the treaty, but it also withdrew. Following the treaty’s demise, the United States was no longer bound by treaty obligations that would prevent it from deploying land-based missiles of this range in either Europe or Asia. The United States could now deploy such missiles on the territory of US allies in Asia as a means of countering China’s growing military power. China therefore opposed US withdrawal from the treaty, just as it had supported the treaty’s signing more than three decades earlier. As part of its effort to drive a wedge between Russia and China on nuclear issues, officials from former US President Donald Trump’s administration reportedly told Chinese officials that if US missiles of this range were to be deployed in Asia, then they should blame Putin, not the United States, for the demise of the treaty that previously stood as an obstacle to such deployments (Detsch & Mackinnon, 2021, April 20).

To date, however, the INF Treaty’s demise has been a source of cooperation between China and Russia. Rather than blaming Russia, as the Trump administration sought, China adopted a relaxed attitude toward the Russian missile deployment, viewing it as understandable in light of US and NATO actions toward Russia. For its part, Russia also took steps to alleviate China’s concerns. Putin vowed that Russia would deploy no missiles previously forbidden by the treaty in any regional theater unless the United States were to deploy them in that theater first. If the United States were to deploy INF-range missiles in Asia, prompting a Russian deployment in response, then China would be unlikely to view the Russian missiles as threatening. The strong China-Russia relationship, which includes regular defense consultations, would offer ample opportunity for Russia to explain its intentions to China and to remove any possible friction (Charap, 2019, April 9, p. 6). Both China and Russia have declared that they would respond to a US deployment of INF-range missiles in Asia with their own force deployments directed against US and allied targets (Blank, 2020b, p. 263–264).

5.5 Multilateral Arms Control

Prospects for multilateral arms control are another area in which potential friction has been minimized as the China-Russia relationship has grown closer. Russian officials have ceased to insist on China’s participation in future arms control negotiations (Pifer, 2020, February 19). During its final year in office, the Trump administration unsuccessfully sought Russia’s assistance in bringing China into a new arms control treaty. In making its case to Russia, the administration shared unprecedented amounts of classified information about China’s nuclear arsenal, including projections of its rapid growth (Sanger & Broad, 2020, July 1, p. A12). Despite these efforts, Russia refused to apply pressure on China. Russian leaders almost certainly would continue to welcome China’s involvement, but they appeared to calculate that pressure would fail to bring China to the negotiating table and would merely antagonize an increasingly important partner. For its part, China has little incentive to join international arms control negotiations in the near future.

This situation further complicates the future of arms control, which is already fraught because of new and disruptive technologies. Russia continues to have an interest in using arms control to maintain strategic parity with the United States. China, by contrast, views arms control as a trap that is designed to stifle its rise. The United States is likely to seek, at a minimum, increased transparency about China’s nuclear program. China is likely to insist that excessive transparency could weaken its nuclear deterrent, especially considering the quantitative and qualitative advantages of the US nuclear arsenal. In view of the increasingly close China-Russia relationship, including cooperation on nuclear issues, the United States is unlikely to accept a situation in which the combined nuclear arsenals of Russia and China gain a significant numerical advantage over the US arsenal (Chase & Carlson, 2019, October, p. 31).

6 Prospects for Cooperation in Nuclear Deterrence

Since 1964, the relationship between Moscow and Beijing in the sphere of nuclear deterrence has evolved continuously. As this chapter has detailed, the relationship was explicitly adversarial for the first two decades before warming considerably during the Gorbachev era and becoming merely implicitly adversarial. Since the onset of the Ukraine crisis, the adversarial elements have faded. Latent deterrence still exists, but it has become much less prominent than it was a decade ago as a result of the strengthened bilateral relationship. As detailed in the previous section, China and Russia have cooperated on many aspects of nuclear deterrence in recent years, reflecting a new, implicitly cooperative phase of relations. These developments raise the possibility that the relationship could develop further and become explicitly cooperative against the United States.

Despite their growing defense cooperation, China and Russia have refrained from the formation of a political-military alliance, largely because both countries wish to maintain diplomatic flexibility and to avoid being drawn into the other’s regional disputes. The 2001 treaty commits both countries to refrain from joining alliances directed against the other and provides for bilateral consultations in the event that either country faces a threat to its security. However, the treaty includes no mutual security guarantee, the crucial feature of an alliance. Both countries maintain that they have no intention to form an alliance, though Putin said in October 2020 that such an outcome was possible (Gabuev, 2020, December 2).

Although it falls short of a formal alliance, the close alignment of China and Russia in recent years has confounded the expectations of many analysts who emphasized the relationship’s likely fragility. This alignment is partly a result of structural factors, as both countries have an incentive to cooperate in order to provide a counterweight to US power. Structural factors alone, however, seem insufficient to explain the relationship. If structure alone mattered, then by now Russia might have sought closer ties with the West in order to balance China’s growing power, as several other countries along China’s periphery have done. In the future, such an outcome remains possible. For now, similarities in national identities and world views bring the two countries together (Rozman, 2014). Putin and Chinese President Xi Jinping share similar views of domestic governance. They bristle at Western criticism of their human rights records and authoritarian rule, viewing such statements as efforts to interfere in their domestic affairs and ultimately to topple their regimes. They also share an antipathy toward conceptions of an international order based on liberal political values (see also Chapter “Russia’s Strategic Outlook and Policies: What Role for China?” by Hannes Adomeit).

These factors create a stable foundation for the relationship that is likely to endure for at least as long as Putin remains in power, a period that could last until 2036 following recent amendments to the Russian constitution. Putin and his advisers appear to have calculated that they have a window of opportunity to cooperate with China in order to increase their leverage in relations with the West. Following the onset of the Ukraine crisis, the Russian government reportedly conducted an inter-agency review of policy toward China that dispelled many concerns about a potential Chinese threat in the near term (Gabuev, 2017, May 24). For its part, China has a strong incentive to maintain Russia’s support, especially in light of its growing rivalry with the United States and rising tensions with several US allies and partners along its periphery (see also Chapter “Imperialist Master, Comrade in Arms, Foe, Partner, and Now Ally? China’s Changing Views of Russia” by Jo Inge Bekkevold).

Given these sources of durability in the relationship, China and Russia are likely to continue their cooperation in maintaining nuclear deterrence of the United States. A shift to explicitly cooperative relations against the United States in nuclear issues appears unlikely, however (Perfilyev, 2018a, December 4; 2018b, December 12). Despite the close relationship that the two countries have built, some important factors are likely to impose limitations on its development. The two countries have a mutual interest in maintaining nuclear deterrence of the United States, but they lack a clear basis for cooperation in the development of strategic offensive capabilities. Russia seeks to maintain its status as a nuclear superpower, and it has no obvious interest in helping China to attain this status. The element of latent deterrence in the bilateral relationship has faded, but it has not disappeared entirely. Russian defense planners must continue to plan for the defense of their eastern territories against a potential Chinese invasion, even if such a possibility appears extremely unlikely for the foreseeable future. Defense planning for this contingency continues to rely on nuclear deterrence. For its part, China must also hedge against future changes in Russian nuclear force deployments (Charap, 2019, April 9, p. 5.)

Russian leaders have made a strategic decision to set aside long-term concerns about China’s rise for now. This decision reflects both their desire for cooperation with China in dealing with the West and their recognition of the damage that Russia’s interests could suffer from a breakdown of relations with China. In the long run, however, Russian leaders must hedge against the possibility that the relationship could deteriorate. One factor that could lead to such deterioration would be the emergence of an assertive or even potentially aggressive Chinese foreign policy that threatened Russia’s interests. If Russian leaders were eventually to conclude that China posed a greater threat than the West, then they could be forced to reconsider their alignment with China and to explore possibilities for closer cooperation with the West in addressing China’s rise.

Such considerations already impose some constraints on the China-Russia relationship, including in the area of bilateral defense cooperation. Russian arms sales to China are a cornerstone of the relationship, as discussed above, but these sales have been subject to important limitations. Russian officials have approved arms sales that improve China’s air, naval, anti-ship, and air defense capabilities, all of which would be useful in maritime contingencies against the United States and its allies in Asia, rather than providing weapons for China’s ground forces that could be used in a potential land invasion of Russia. Similarly, Russia has no obvious interest in strengthening China’s nuclear arsenal, assisting China with the development of hypersonic weapons, or otherwise enhancing China’s strategic offensive forces.

Despite these constraints, Western leaders should expect continued and potentially even strengthened China-Russia defense cooperation in the coming years, including in the area of nuclear deterrence. The two countries are likely to continue their efforts to maintain nuclear deterrence of the United States by opposing the deployment of US missile defense systems and high-precision conventional weapons. They are likely to apply pressure on US allies in Asia and Europe to reject the deployment of missile defense systems, land-based intermediate-range missiles, and other weapons systems on their territories. China-Russia cooperation could also take more surprising forms, including possible joint air and missile defense in the Arctic or even the deployment of Chinese SSBNs to this region, with Russia’s approval, for deterrence against nuclear attacks. The latter possibility, which the 2019 Department of Defense report on China’s military raised, has been a subject of discussion in Russian military analysis. Such deployments would not only reduce the vulnerability of Chinese SSBNs but also bring them within much closer range of potential targets (Goldstein, 2019, June 1; Department of Defense, 2019, pp. v, 114).

It is even possible to imagine scenarios of military conflict in which China and Russia might collaborate to ensure nuclear deterrence of the United States. Northeast Asia is a likely focus of such scenarios. A potential military conflict on the Korean Peninsula, in which both the Russian and Chinese nuclear forces would be factors, looms as one possibility. A two-front war that would force the United States and its allies to confront Russia in Europe and China in Asia simultaneously is another (Carlson, 2021). In such a scenario, both countries might introduce the risk of nuclear escalation in their respective theaters. Even if China and Russia refrain from cooperation in the development of strategic offensive capabilities, their cooperation in various aspects of nuclear deterrence could create pressing challenges for Western leaders and defense planners.