Table of Contents

The survivability of Chinese SSBNs and the resulting impact on strategic stability in the Asia Pacific are shaped not only by the structural features and operational practices of China’s submarines but also by how the United States and its regional partners respond to China’s nuclear submarine fleet. These rival ASW capabilities also have important ramifications for the operational strategy China adopts for its SSBNs and, hence, affect the risks of a conventional conflict and inadvertent escalation as well.

The threat that the ASW capabilities of the United States, Japan, and other U.S. regional allies pose to China’s SSBNs has significantly affected their survivability and has important implications for strategic stability.

China’s Threat Perceptions

The United States and its allies wield a variety of ASW platforms that could threaten China’s SSBNs. These assets include attack submarines, ASW-capable surface ships, maritime ASW aircraft, and surveillance ships that can prepare for and assist in ASW operations. Chinese concerns are exacerbated by continued U.S. freedom of navigation operations off China’s coast and the continued reinvigoration of U.S. ASW capabilities.

Geography lends various advantages to the United States’ and its allies’ efforts to block Chinese SSBNs from patrolling in the Pacific Ocean. The biggest roadblock is the existence of major chokepoints separating China’s coastal waters from the Pacific Ocean. Along the First Island Chain, there are only a limited number of waterways—including the Miyako Strait and the Bashi Channel (in the Luzon Strait near the Philippines)—through which Chinese SSBNs can transit. All of these waterways are adjacent to land features possessed or controlled by U.S. allies, so the passages are under close surveillance by U.S. or U.S.-friendly ASW forces.

In fact, some Japanese defense officials used to boast that Chinese submarines would not be able to slip into the Pacific through the Ryukyus, a chain of islands scattered along the north and south of Taiwan, or through the Bashi Channel without being detected by U.S. and Japanese ASW systems.1 Indeed, there have been cases when foreign countries have reportedly detected Chinese SSNs in transit. In 2004, for example, a Chinese 091-class nuclear attack submarine was reportedly detected by Japanese, Taiwanese, and U.S. ASW platforms as the submarine sailed from the Western Pacific back to China, passing through Japanese waters.2 Similarly, in January 2018, a Chinese 093-class SSN—which is believed to be considerably quieter than the 091-class SSN, and which may have a noise level similar to that of the 094-class SSBN—was reportedly detected by Japan while it was submerged near the Diaoyu/Senkaku Islands.3 Notably, Chinese SSBNs face greater geographical constraints today than Soviet SSBNs did during the Cold War. The barrier formed by Greenland, Iceland, and the UK that Soviet SSBNs needed to pass through to reach the North Atlantic Ocean is much wider than the waterways in the First Island Chain.

To compound the geographical advantages that China’s rivals enjoy, the United States and its allies have significantly augmented their sound surveillance networks in and around the Pacific in recent decades, in the face of increasing Chinese submarine activity.4 The United States even has reportedly extended its underwater hydrophone systems to the south of the Philippines to connect with islands belonging to Indonesia and, from there, north to India’s Andaman Islands.5 This all-encompassing, seamless network—known as the U.S. Navy’s Fish Hook Undersea Defense Line—has the potential to seriously undermine Chinese SSBNs’ ability to leave China’s coastal waters and sail into the Pacific or Indian Oceans.

Beyond Chinese concerns about detection, the United States could undermine the efficacy of China’s sea-based nuclear deterrent by interfering with its command, control, and communications (C3) system. Foreign analysts have long raised doubts about China’s ability to maintain reliable communication channels with SSBNs operating in distant oceans.6 Conducting long distance communications with a submerged SSBN is challenging, though Beijing has been seeking to improve in this area. Open-source research indicates that China is now capable of communicating with submarines at super low frequencies (SLF) of 30–300 hertz.7 In 2009, China reportedly completed construction on its first military SLF transmission station and conducted several tests. One year later, a Chinese nuclear submarine successfully received messages from the SLF transmission station, as China became the third country in the world to establish a comparable submarine communications system.

Geography lends various advantages to the United States’ and its allies’ efforts to block Chinese SSBNs from patrolling in the Pacific Ocean.

There is some evidence that this system has been effective at enabling Chinese submarine operations far from China’s shores. In 2013, a Chinese nuclear attack submarine completed a successful patrol in the Indian Ocean and reached as far as the Gulf of Aden.8 After that, CCTV reported during an episode of its Military Reports (Junshi Baodao) program that China has established regular patrols of nuclear attack submarines for anti-piracy escort missions near the Gulf of Aden.9 Where there may be other means of communicating with these SSNs, such as satellites or local surface ships, some independent Chinese analysts have cited such patrols as indirect evidence that China has achieved reliable radio communication with its nuclear submarines at very long distances.10

Furthermore, China is believed to be conducting research on extremely low frequency (ELF) radio communications,11 a technology that would facilitate contact with submarines in very deep water (more than 100 meters) and would further enhance the survivability of Chinese submarines.12 In addition, an airborne C3 system similar to the U.S. TACAMO (take charge and move out) is thought to be under development.13 Furthermore, China has long explored the possibility of using satellites for submarine communications.

Jointly, these technologies could provide an increasingly diversified C3 system for Chinese SSBNs. That said, all these communication methods have shortcomings. Airborne systems are vulnerable to air-defense weapons. Submarines must come close to the surface to receive signals from satellites. And ground-based transmitters can be held at risk with high-precision conventional munitions. Such vulnerabilities create potential opportunities for enemy exploitation that must be taken into account.

The Motivations Behind and Character of U.S. Anti-submarine Warfare

In light of the vast scope of U.S. and allied ASW capabilities, it is crucial to explore the motivations and strategy that shape how Washington and its partners employ these assets. To put the discussion into perspective, it is worthwhile to first distinguish between two types of operations for countering enemy submarines. Strategic ASW aims to counter an adversary’s SSBNs. By contrast, tactical ASW is directed at a foe’s attack submarines or other general-purpose submarines. In wartime, strategic ASW would involve intentionally tracking and potentially attacking an adversary’s SSBNs.

It is important to use the qualifier “intentionally” because, during an unexpected encounter with an enemy submarine, it may be unrealistic to expect a naval commander to try to determine whether the enemy submarine is carrying nuclear missiles before launching an attack. During peacetime, if an enemy SSBN is encountered by chance, it is common to try to trail it and gather intelligence. By contrast, strategic ASW during peacetime would involve efforts to deliberately seek out enemy SSBNs even if there is no other reason to expect one to be operating in a given area.

China’s view is that the United States and its allies should not conduct strategic ASW against its SSBNs because doing so would undermine China’s confidence in its SSBN forces’ survivability and, hence, have a negative effect on strategic stability. Much of the U.S. policymaking community seems to agree that deliberately targeting Chinese SSBNs with its ASW capabilities would be counterproductive. Indeed, the mainstream views in Washington (at least among analysts) are that the United States should not seek to undermine China’s second-strike capability and that the U.S. military very likely does not and will not have the capability to fully neutralize China’s strategic deterrent. The 2009 Nuclear Posture Review and the Ballistic Missile Defense Review, which set out Obama administration policy, both explicitly stated that the United States is committed to maintaining strategic stability with China.14 Beijing understands this statement to mean that Washington has essentially committed not to seek to undermine China’s second-strike capability. To some extent, this understanding has since served as an important foundation for a stable U.S.-China nuclear relationship.

Much of the U.S. policymaking community seems to agree that deliberately targeting Chinese SSBNs with its ASW capabilities would be counterproductive.

Policy documents from the Trump administration appear to have softened that stance somewhat, but these documents do not convey an overt intention to upset strategic stability vis-à-vis China. The latest Nuclear Posture Review, released in February 2018, only mentions strategic stability in general terms and does not explicitly pledge to maintain bilateral strategic stability with China.15 Moreover, the report’s section on China emphasizes the importance of deterring Chinese non-nuclear strategic attacks by means of U.S. nuclear capabilities and maintaining an escalation dominance capability against China “at any level of escalation.” Such narratives signal an increasingly confrontational approach, rather than a cooperative nuclear relationship based on a de facto recognition of mutual vulnerability. That said, the Trump administration’s National Security Strategy, released in December 2017, does state that “Enhanced missile defense is not intended to undermine strategic stability or disrupt longstanding strategic relationships with Russia or China.”16 The impact of such language on China’s thinking about its nuclear relationship with the United States remains to be seen.

Yet U.S. civilian policymakers and military brass do not seem wholly in sync on the issue of whether ASW capabilities should be used against Chinese SSBNs. Whatever approach the United States adopts in its declaratory policy, the U.S. Navy, at an operational level, appears to be interested in developing and exercising a strategic ASW capability against China. If so, there appears to be a disconnect between political and operational U.S. actors, given that U.S. civilian decisionmakers do not seem to have a clear policy on conducting strategic ASW operations against China.

For their own part, some U.S. military officials have voiced alarm about the implications of China’s SSBNs. For example, Admiral William Gortney, when he was at the helm of U.S. Northern Command, painted China’s SSBNs as a concern in the general sense that they could eventually threaten the U.S. homeland.17 Captain James Fanell, a former director of intelligence and information operations for the U.S. Pacific Fleet, testified to the U.S. House of Representatives in 2018 that the U.S. Navy must ensure at all times “that every time a [PLA Navy] SSBN departs on a strategic nuclear patrol, the [U.S. Navy] must follow closely enough to be ready to sink them if they ever attempt to launch a nuclear tipped ICBM towards our shores.”18 The underlying thinking of concerned U.S. military officials appears to be that the introduction and improvement of China’s sea-based nuclear capabilities could eventually remove any doubt that China has a secure second-strike capability and could, therefore, remove the option for the United States to conduct a first strike against Chinese nuclear forces in a crisis.

Again, the history of U.S.-Soviet (and later U.S.-Russian) nuclear interactions is instructive. In the late 1960s, the Soviet deployment of the Yankee-class SSBN—the first Soviet SSBN with firepower comparable to that of its U.S. SSBN peers—helped change the threat perceptions of the United States.19 According to one pair of prominent U.S. scholars, this deployment “convinced President Nixon that the United States no longer possessed a viable damage limitation option against Soviet nuclear forces,” and it “accelerated a shift in U.S. thinking towards escalation control options in the U.S.-Soviet nuclear competition.”20 Subsequently, the U.S. Navy poured significant resources into strategic ASW against Soviet SSBNs, an approach that (from a U.S. perspective) was rather successful.21

In a similar sense, while China’s first-generation 092-class SSBN had serious technical problems and never conducted any patrols, the development and deployment of China’s second-generation SSBNs may start to represent a more realistic threat to the United States, like the Soviet deployment of the Yankee-class SSBN. As a result, the United States may have incentives to seek to develop an effective strategic ASW capability against Chinese SSBNs in an attempt to avoid the undesirable prospect of mutually assured destruction with China—as Washington did with Moscow during the Cold War.

U.S. allies in the region, too, may view China’s growing SSBN capability as a potential threat. In theory, SSBNs could enhance China’s nuclear retaliation capability against regional targets, such as U.S. military bases in Japan and South Korea. Although China has categorically renounced the option of using nuclear weapons against non-nuclear-weapon states, Tokyo and Seoul may not be entirely reassured. More importantly, China’s growing SSBN capability may increase the concerns of U.S. allies about decoupling—the possibility that more credible nuclear threats to the United States itself might leave Washington less willing to come to allies’ defense. These concerns may motivate these U.S. partners to work with Washington to counter China’s SSBNs in the region.

Presumably motivated by these threat perceptions, the U.S. Navy openly advertised its efforts to use U.S. SSNs to track, and if necessary, sink Chinese SSBNs.22 Even before that, there were Chinese reports of joint military exercises held by the United States and its regional allies to practice hunting Chinese SSBNs.23 Such revelations are unnerving but not surprising, for China has always suspected that Washington is determined to undermine China’s sea-based nuclear deterrent. Chinese experts point to collective efforts by the United States and its allies to enhance their ASW capabilities in the Asia Pacific as strong evidence of such intentions.24 Moreover, some U.S. experts openly call for holding Chinese SSBNs at risk, further raising Chinese concerns. In particular, because of the challenges involved in intercepting Chinese SLBMs after a potential launch, some U.S. experts argue that the safest way to eliminate any future threat from Chinese SLBMs would be to hold Chinese SSBNs at risk so they can be destroyed preemptively before their SLBMs can be launched.25

There may be other incentives for Washington to develop strategic ASW capabilities against China. Although it is a minority view that does not appear to have found official favor, some U.S. experts argue that U.S. strategic ASW capabilities could force China to devote a significant fraction of its attack submarine fleet to protecting Chinese SSBNs, thereby reducing the number of Chinese attack submarines available to conduct other missions, such as offensive operations against U.S. surface ships.26 The United States openly adopted this approach against the Soviet Union toward the end of the Cold War (albeit to unknown effect). Finally, tradition and bureaucratic inertia may contribute to a U.S. interest in developing strategic ASW capabilities against China. After all, U.S. submarine forces have long been trained to track and trail Soviet (and later Russian) SSBNs and have long sought to hold these submarines at risk at all times. In the absence of a decision by the U.S. national leadership not to try to hold Chinese SSBNs at risk, the U.S. Navy might, by default, have applied the same approach to China’s emerging SSBN fleet.27

The Added Difficulty of Distinguishability

Even if the United States were willing to refrain from deliberately conducting strategic ASW against China, it would be difficult to completely distinguish strategic ASW operations from tactical ASW operations that are not aimed at Chinese SSBNs. This is an important consideration because the United States has a strong interest in developing and deploying ASW forces to counter certain nonstrategic Chinese submarines. Apart from its SSBN fleet, China’s nonstrategic SSNs and diesel-electric submarine fleets are growing rapidly in terms of size and capabilities. These submarines may become targets for U.S. ASW capabilities because of the important roles they play in conducting anti-surface warfare, gathering intelligence, escorting surface fleets, and supporting special forces.

The challenge for Washington to demonstrably distinguish between its strategic and tactical ASW operations is somewhat similar to U.S.-Chinese interactions with respect to China’s land-based ballistic missiles. The United States, especially under the Obama administration, has implied that it does not seek to intentionally threaten China’s long-range nuclear ballistic missiles, but the U.S. government has openly indicated an interest in developing missile defense capabilities to counter shorter-range Chinese regional missiles.28

Even if the United States were willing to refrain from deliberately conducting strategic ASW against China, it would be difficult to completely distinguish strategic ASW operations from tactical ASW operations.

For example, Washington has repeatedly sought to reassure China by declaring that U.S. missile defense systems are not designed to threaten China’s nuclear ICBMs and do not have the capability to do so.29 However, Washington has deployed regional missile defense capabilities in the Asia Pacific that are partially aimed at intercepting China’s regional missiles.30 Indeed, in its 2009 Ballistic Missile Defense Review, the United States explicitly stated that “it is important that China understand that the United States will work to ensure protection of our forces, allies, and partners in East Asia against all regional ballistic missile threats.”31 China has not completely accepted the distinction between strategic and regional missile defense systems that the United States is trying to draw, but U.S. efforts may go some way toward clarifying its intentions.

This concern is magnified in the case of Chinese submarines and their maritime environment. Especially given the extreme secrecy surrounding submarine operations, it would be even more difficult to separate strategic and tactical operations underwater than it is on land. Wu Riqiang, for example, is concerned that Chinese SSBNs and SSNs may not be easily distinguishable underwater.32 In theory, China could base SSBNs at separate ports to help make its SSBNs more easily distinguishable from other submarines. If Beijing were to do so, Washington could more readily delineate between strategic and tactical ASW, and the United States could then—as a confidence-building measure and a gesture of good will—refrain from targeting Chinese SSBN bases in a conflict and from conducting surveillance against them during peacetime.

In practice, however, Chinese SSBNs are invariably commingled with other submarines at ports. The newly built submarine base near Sanya on Hainan Island, for example, is frequently visited by both SSBNs and nonstrategic attack submarines. This practice is quite common. In fact, all British, Indian, Russian, and U.S. naval bases that host SSBNs also serve other functions, including hosting other types of nonstrategic submarines.33 The French naval base at Brest is the only one in the world that only hosts SSBNs, and France’s decision to do so is probably due to geographical constraints.34 Moreover, in addition to shared ports, it is hard to imagine that China would willingly declare separate operating areas for SSBNs and attack submarines, especially when almost no other countries have opted to do so.

Implications for Crisis Stability

The prospect of U.S. ASW capabilities aimed at Chinese SSBNs could threaten crisis stability by posing sobering escalation risks that bear reflecting on, even in light of the perceived past benefits of targeting Soviet submarines during the Cold War. One perceived advantage of U.S. ASW operations against Soviet SSBNs was that, in the early stages of a hypothetical military conflict, Washington could discourage Moscow from further escalating by preemptively destroying Soviet SSBNs and thereby significantly reduce Soviet nuclear forces.35 It is unknown whether the United States embraces such thinking against China today. If it does, this approach would be very problematic in terms of managing escalation. Washington may hope that a preemptive attack on Chinese SSBNs would discourage escalation, but the risk of an escalatory Chinese response could not be easily ruled out.

Short of attempting to destroy an adversary’s SSBNs, U.S. efforts to interfere with an enemy’s ability to communicate with its nuclear-armed submarines could create escalation risks of their own. During the Cold War, the United States tried to exploit vulnerabilities in Moscow’s nuclear C3 systems, including those associated with the Soviet SSBN fleet. The hope was that, if necessary, the United States could prevent the Soviet high command from issuing launch orders to its SSBNs.36 Knowing this history, Chinese SSBN commanders could misinterpret an external disruption of their C3 systems as a hostile attempt to disable China’s sea-based nuclear deterrent or even as hostile preparations for a disarming strike. There would be a particularly high risk of misinterpretation if China’s SSBNs share some C3 infrastructure with the country’s attack submarines, as some U.S. experts believe to be the case.37 If so, an enemy strike against this shared C3 system—even if conducted exclusively to undermine China’s conventional military capabilities—could be misinterpreted by Beijing as an attempt to cut off communications between Chinese leaders and their SSBNs. This scenario would create serious risks of escalation.

The prospect of U.S. ASW capabilities aimed at Chinese SSBNs could threaten crisis stability by posing sobering escalation risks.

Moreover, the growing interactions between China’s nuclear assets and other countries’ conventional weapons will pose new challenges. Prior to China’s first SSBN patrols, all the country’s nuclear weapons were deployed exclusively on Chinese territory. With Chinese SSBNs now operating at sea, it is inevitable that the chance of foreign conventional military assets directly confronting Chinese nuclear delivery systems will rise. As early as the mid-2000s, there were Chinese reports of joint naval exercises between the United States and its regional allies to “hunt down strategic nuclear submarines” from “Country C [which is generally believed by Chinese experts to be a thinly veiled reference to China].”38

Intensified cat-and-mouse games between Chinese SSBNs and enemy ASW platforms have already greatly heightened the risks of an incident during peacetime sparking a conventional military conflict. Potentially dangerous encounters between the Chinese and U.S. militaries are increasing. In many of these cases, China has acted preemptively to remove potential threats to strategic nuclear assets. In recent years, for example, the United States has ramped up its airborne maritime surveillance activities with P-8A aircraft over the South China Sea. Some of these operations focus on tracking or collecting intelligence about Chinese nuclear submarines, a practice that has prompted Beijing to scramble fighter jets on many occasions to intercept U.S. aircraft.39

In addition, there have been encounters between U.S. surveillance vessels mapping the sea floor close to China’s nuclear submarine base and Chinese naval ships and maritime militia vessels that were dispatched to disrupt such surveillance.40 Notably, in December 2016, a Chinese naval ship seized a U.S. underwater drone in the South China Sea, despite protests from the nearby U.S. naval surveillance ship that was operating it. The incident increased military and political tensions between the Chinese government and the soon-to-be-inaugurated Trump administration. Some Chinese analysts have since argued that China was attempting to prevent the drone from conducting activities potentially threatening to Chinese SSBNs.41

Dangerous encounters involving Chinese SSBNs might grow in number as the United States and its allies enhance their efforts to counter the emerging Chinese SSBN fleet. Because of the involvement of SSBNs, the perceived stakes in such confrontations might be much higher than other confrontations involving purely conventional military forces. In such cases, more rapid escalation is a possible result.

Dangerous encounters involving Chinese SSBNs might grow in number as the United States and its allies enhance their efforts to counter the emerging Chinese SSBN fleet.

These interactions may impose a new degree of pressure on China’s unconditional no-first-use (NFU) policy—a commitment that the country will never or under any conditions use nuclear weapons first. If Chinese SSBNs are threatened by rigorous non-nuclear ASW operations, China’s leadership will face the dilemma of deciding whether to continue to uphold an unconditional NFU policy. Beijing is fully aware that this policy would constrain its response options if a Chinese SSBN were to be sunk and would, therefore, likely encourage enemies to vigorously track and trail Chinese SSBNs. So far, China has not indicated that it is reconsidering its NFU policy as a result of introducing an SSBN fleet.42

But whether it does so in the future may depend, in part, on how vigorously the United States and its allies pursue ASW in China’s coastal waters and how much of a threat China perceives such activities to pose. In fact, if China were to relax its NFU commitment in the future—and indicate that it might consider launching SLBMs during a conventional conflict—adversaries would be further incentivized to pursue more aggressive strategic ASW against Chinese SSBNs, potentially resulting in a negative action-reaction cycle. China needs to find ways to discourage preemptive attacks on its SSBNs other than relaxing the unconditional NFU policy.

Risks of Chinese Conventional-Nuclear Entanglement

A further specific risk of crisis instability comes from China’s reported interest in using future SSBNs as platforms for deploying both nuclear and conventional weapons. If Beijing implemented such a deployment strategy, the risk of U.S. tactical ASW operations inadvertently undermining Chinese SSBN forces would increase greatly.

The reasoning behind this suggested commingling is that some Chinese analysts and commentators view SSBNs as holding limited value compared to other military assets. They point out that SSBNs are intended to play only a comparatively narrow role—launching strategic nuclear counterstrikes after China is attacked by nuclear weapons. (After all, under China’s NFU policy, all of its nuclear weapons have this same function.) In a military crisis, SSBNs cannot help resolve a regional maritime conflict, escort other ships, or conduct ASW operations. In peacetime, they can rarely contribute to military diplomacy through overseas visits or contribute to counterpiracy, counterterrorism, or refugee/expatriate rescue missions.43

In light of the narrow military utility of SSBNs and their high maintenance costs, Chinese analysts have proposed a range of ideas to make the most out of China’s SSBN investment. Many of these proposals involve mixing nuclear and conventional weapons on the same submarine. These ideas present a serious challenge to the traditional wisdom of making nuclear deterrence the sole mission for SSBNs—though none of these proposals has become government policy yet.

One example is an argument made by some analysts that China’s 094-class SSBNs should be equipped with JL-2 missiles armed with conventional warheads. Although this would be a costly way to use the JL-2 SLBM, these analysts argue that this approach would provide SSBNs with the ability to conduct attack missions against fixed land-based targets. Similarly, some military analysts (including former PLA officers) have proposed on CCTV that submarine-launched variants of the DF-21D and DF-26 anti-ship conventional ballistic missiles should be developed and carried by China’s SSBNs. This idea may be technically feasible since the DF-21 was, in fact, originally developed from China’s first-generation SLBM. Supporters of this approach argue that it could greatly enhance China’s capability to hold U.S. aircraft carriers and other high-value surface ships at risk.44 In fact, even some U.S. experts have suggested that China may consider arming SSBNs with conventional anti-ship ballistic missiles and/or land-attack cruise missiles.45

This interest among some Chinese experts in making the SSBN a multi-mission platform seems to be inspired, in part, by (incorrect) beliefs about U.S. policy. Various Chinese experts wrongly believe that future U.S. Columbia-class SSBNs will be powerful multi-mission platforms,46 even though there is no evidence that Washington is planning to put offensive conventional weapons on this ship (except for a number of conventional torpedoes for defensive purposes).47

Most notably, an article published in China National Defense News, a major official PLA newspaper, states that “the U.S. SSBN (X) can be armed with conventional medium-range ballistic missiles, cruise missiles, and can even launch UAVs [unmanned aerial vehicles] and anti-missile interceptors from underwater.”48 (SSBN (X), which will replace the U.S. Ohio-class SSBNs, has since been renamed the Columbia-class.) The article goes on to argue that, with these capabilities,

strategic ballistic missile submarines will be no longer only a tool of symbolic deterrence but a dual nuclear conventional system for both defensive and offensive purposes, which can be forward deployed with sufficient tactical flexibility, and can be connected with the U.S. space, missile defense and ground combat systems, to become an integrated striking force. This will greatly affect the existing global balance of military power.49

The article concludes by arguing that SSBNs armed with various conventional weapons “may become an important concept for major powers to design and construct large strategic nuclear submarines in the future.”50

Song Zhongping, a retired PLA officer and prominent military commentator on official Chinese media outlets, made an even more radical statement by claiming that countries’ SSNs and SSBNs in the future will become integrated, implying that the differences between them will gradually disappear.51 Following this line of thinking, some Chinese analysts have proposed that Beijing should consider arming its 093-class SSN with the CJ-10 nuclear-armed cruise missile (in addition to conventional weapons) to further diversify China’s nuclear second-strike platforms.52 Again, this idea does not necessarily represent Chinese government policy or thinking, but if it or similar concepts are implemented in the future, the implications could be very negative.

Mixing nuclear and conventional weapons on the same platform—either by arming SSBNs with conventional offensive weapons or by arming SSNs with nuclear weapons—would blur the line between nuclear and conventional forces.

Mixing nuclear and conventional weapons on the same platform—either by arming SSBNs with conventional offensive weapons or by arming SSNs with nuclear weapons—would blur the line between nuclear and conventional forces. If this were to happen, a U.S. attack aimed at neutralizing Chinese conventional weapons might unintentionally compromise Chinese nuclear capabilities. In such a case, China could conclude, incorrectly, that the United States was seeking to destroy its nuclear deterrent, a situation that would result in dangerous and unnecessary escalation risks.

Implications for Arms Race Stability

Beyond the aforementioned complications involving escalation risks in a crisis, U.S. efforts to target Chinese SSBNs with its ASW capabilities would also have a direct bearing on Chinese and U.S. naval procurement decisions in the coming years.

After all, if the United States seeks to wield a strategic ASW capability against China, it is uncertain that it would succeed. However, China cannot be sure that its SSBNs will be safe in the future, particularly if they become targets for enemy ASW capabilities. If both countries continue on this course, this dual uncertainty may encourage each side to invest even more heavily in this competition to try to shift the balance in its own favor. So far, Washington has not started to increase its SSN forces, but there are growing domestic calls to do so. Moreover, the United States has already taken measures to increase its production capacity so that, if needed, it can roll out new SSNs more quickly.53 If not well managed, these dynamics could evolve into a direct arms competition.

The insufficient quietness and limited survivability of China’s existing SSBNs could further motivate the U.S. Navy to pursue strategic ASW efforts, believing that such operations would be relatively easy. Such U.S. attempts could, in turn, induce China to build a bigger SSBN fleet (with longer-range missiles) to increase the fleet’s overall survivability, even before China masters the technology to build much quieter SSBNs. Such an arms race would surely be very costly and destabilizing.

U.S. efforts to target Chinese SSBNs with its ASW capabilities would also have a direct bearing on Chinese and U.S. naval procurement decisions in the coming years.

Assuming that SSNs are the United States’ most important ASW asset for countering Chinese SSBNs (as is generally believed), it is worthwhile for both U.S. and Chinese strategists to examine whether Washington theoretically would have enough military resources to develop a viable strategic ASW capability against China. Existing U.S. assessments indicate that Beijing currently possesses four operational 094-class SSBNs and may build a total of five to eight such boats. When China starts to construct the 096-class SSBNs in the early 2020s, that number could further grow.54

With a total of five 094-class SSBNs, China may be able to keep one or two of them at sea at all times.55 If Beijing has eight SSBNs, it may be able to keep two to four of them at sea. The exact number would depend on a series of factors, including whether China can prepare two sets of crews for each SSBN, whether Beijing has an effective logistical support system to maximize the time that its SSBNs can spend at sea, and the lifetime of Chinese reactor cores. In any case, these estimates are consistent with a general consensus among Chinese and foreign experts that Beijing is likely to maintain a total of fewer than ten SSBNs and to want to keep somewhere between one and three of them on constant patrol. (Having more than one SSBN on patrol would hedge against the risk of one of them falling prey to enemy ASW operations.)56

Given this baseline, it is possible to estimate how many SSNs the United States would need to track patrolling Chinese SSBNs. Based on Cold War experience, some U.S. experts assume that the United States would need to possess five SSNs to keep track of each Chinese SSBN at sea.57 This estimate takes into consideration all the time that SSNs need for transit, training, and maintenance. This figure seems to be generally consistent with the historical record of the 1980s, when the Soviet Union kept about six to twelve SSBNs at sea and the United States was more or less able to shadow them with a total inventory of about 100 SSNs, a considerable number of which were probably forward deployed and charged with the mission of tracking Soviet SSBNs during peacetime.58

The assumption that five U.S. SSNs are needed to track each enemy SSBN only applies, however, to situations in which U.S. SSNs are able to quickly pick up their targets as or shortly after the SSBNs leave port. During the Cold War, if a Soviet SSBN was able to reach its patrol area and then disappear before U.S. SSNs could start tracking it, U.S. forces had a much harder time finding it again. The scale of this challenge depended on a range of variables, including the specific patrol tactics used by Soviet SSBNs. When Soviet nuclear-armed submarines started to adopt more advanced technologies and became quieter toward the late 1980s, it became even more difficult for the United States to keep track of them. Owen R. Cote, a highly regarded U.S. expert on ASW, goes as far as to say that “[there were] several incidents in which the entire [U.S.] Navy had to deploy in order to find and maintain contact on one [Soviet] submarine.”59

In the U.S.-China case, if Beijing keeps between one and three SSBNs at sea, Washington would need to devote five to fifteen SSNs to tracking and trailing them, assuming that SSNs are the primary U.S. ASW platform deployed against Chinese SSBNs. If Washington supplements its SSNs with other ASW platforms, the required number of SSNs could go down. That said, contrary to the Cold War, when the primary mission of U.S. SSNs was to conduct strategic ASW against Soviet SSBNs, existing U.S. SSNs are probably primarily assigned to missions other than tracking SSBNs, let alone just Chinese ones. Today U.S. SSNs are involved in conducting anti–surface ship operations, protecting U.S. surface ships, intelligence collection, offensive and defensive mine warfare, and supporting special operation forces, among others.60

Between 2006 and 2016, the U.S. Navy maintained a constant goal of possessing forty-eight SSNs; then, in 2016, the goal was raised to sixty-six submarines.61 With forty-eight SSNs, it would be challenging for the United States to devote enough of them, on a full-time basis, to the strategic ASW mission against China. This would be especially true if the required number of submarines for the mission were near the upper range of fifteen SSNs. How much this calculus will change when the new goal of sixty-six SSNs is achieved is unknown.

Although the relevant U.S. literature often cites China’s growing naval power as the main reason for raising the United States’ SSN goal, it is difficult to know if, or to what extent, this new requirement was motivated by efforts to counter future Chinese SSBNs or other naval capabilities.62 That said, U.S. analysts have indicated that, during a crisis involving China, the United States could increase the number of SSNs tasked with tracking down Chinese SSBNs (at the expense of other missions).63 This surge capability could help the United States avoid having to dedicate a certain number of SSNs to strategic ASW missions against China at all times, further reducing the numerical requirement for U.S. SSNs. Such a surge strategy may involve some drawbacks, because not having the SSN crews practice tracking Chinese SSBNs during peacetime may undermine their ability to do so in a crisis. But these considerations may be secondary for U.S. naval planners.

Another complication for Washington is that, given the projected force level of the U.S. SSN fleet over the next few decades (shown in figure 2), the United States will be hard-pressed to maintain a force of forty-eight SSNs for a window between 2025 and 2031 or a force of sixty-six SSNs between now and 2047. If Washington is to conduct systematic strategic ASW against Chinese SSBNs, including in peacetime, it may need to introduce even more SSNs (beyond those currently planned) in the near to medium term. It may be difficult to do so, as the U.S. submarine production industry will already be stretched to build two Virginia-class SSNs per year over the next three decades when it also needs to divert resources into building the new Columbia-class SSBNs.64

Given these competing dynamics, there is a dual uncertainty shared by Beijing and Washington about whether Chinese SSBNs could be shielded from U.S. ASW capabilities and whether the United States would have enough SSNs to make a credible attempt to track Chinese SSBNs (if it chose to try). This uncertainty could create incentives for both countries to increase their production capacities more than they otherwise would—an outcome that would have deleterious consequences for arms race stability.


1 Yoshihara and Holmes, “China’s New Undersea Nuclear Deterrent: Strategy, Doctrine, and Capabilities.”

2 Wang and Ye, “Lessons for China’s Nuclear Submarine Penetration From the Sino-Japanese Nuclear Submarine Incident” [从中日核潜艇事件看我核潜艇的突防].

3 Liu Zhen, “Is China’s Nuclear Attack Submarine Too Easy to Detect?,” South China Morning Post, January 28, 2018,

4 Lyle J. Goldstein and Shannon Knight, “Wired for Sound in the ‘Near Seas,’” Proceedings, no. 4.

5 Desmond Ball and Richard Tanter, The Tools of Owatatsumi: Japan’s Ocean Surveillance and Coastal Defence Capabilities (Canberra, Australia: Australian National University Press, 2015).

6 Stephen Polk, “China’s Nuclear Command and Control,” in China’s Nuclear Force Modernization, ed. Lyle J. Goldstein and Andrew S. Erickson (Newport, Rhode Island: Naval War College Center for Naval Warfare Studies, 2005).

7 “China’s Super Low Frequency Deep Water Submarine Communication System Comes Online” [我国建成超低频对潜深水通信系统], Geren Tushuguan, August 9, 2016,

8 Vijay Sakhuja, “Chinese Submarines in Sri Lanka Unnerve India: Next Stop Pakistan?,” Jamestown Foundation China Brief 15, no. 11 (2015).

9 “China’s Nuclear Submarine Completed Escort Mission in Gulf of Aden, Starting to Achieve Regular Patrols” [中国核潜艇完成亚丁湾护航 初步实现常态化], Guanchazhe Wang, April 26, 2015,

10 Xie Ruiqiang (谢瑞强), “Mainland Nuclear Submarine’s First Sail in Indian Ocean” [大陆核潜艇首航印度洋], Phoenix Weekly (凤凰周刊), 2014.

11 The definitions of SLF and ELF are sometimes not standardized across countries. In this paper, SLF refers to the frequency spectrum between 30 and 300 hertz, and ELF refers to the frequency spectrum between 3 and 30 hertz.

12 It is necessary to note that ELF has a very low data transmission rate, and Chinese submarines would still need to come to periscope depth to receive longer messages and more detailed instructions. Zhuo Xianjun (卓贤军) et al., “The Extremely Low Frequency Engineering Project Using Wem for Underground Exploration” [极低频探地 (Wem) 工程], Engineering Sciences (中国工程科学) 13, no. 9 (2011); and “China’s Super Low Frequency Deep Water Submarine Communication System Comes Online” [我国建成超低频对潜深水通信系统].

13 Wu Riqiang (吴日强), “Have China’s Strategic Nuclear Submarines Started Operational Patrols?” [中国战略核潜艇开始战备巡航了吗?] Modern Ships (现代舰船), no. 2 (2016).

14 U.S. Department of Defense, “Nuclear Posture Review Report” (Washington DC: Department of Defense, Office of the Secretary, 2010); and U.S. Department of Defense, “Ballistic Missile Defense Review Report” (Washington DC: Department of Defense, 2010).

15 U.S. Department of Defense, “Nuclear Posture Review Report” (Washington, DC: Department of Defense, Office of the Secretary, 2018),

16 White House, “National Security Strategy of the United States,” White House, December 2017,

17 Bill Gertz, “Northcom: China’s Three Missile Submarines a ‘Concern,’” Washington Free Beacon, April 7, 2015,

18 James Fanell, China’s Worldwide Military Expansion, Hearing Before the House Permanent Select Committee on Intelligence, 115th Cong. (2018) (testimony by James Fanell, former U.S. Navy Director of Intelligence and Information Operations (May 17, 2018).

19 Samuel Bell, “The Impact of the Type 094 Ballistic Missile Submarine on China’s Nuclear Policy.”

20 Roy Kamphausen and Andrew Scobell, “Right Sizing the People’s Liberation Army: Exploring the Contours of China's Military,” U.S. Army War College Strategic Studies Institute, September 2007.

21 Barry R. Posen, Inadvertent Escalation: Conventional War and Nuclear Risks (Ithaca and London: Cornell University Press, 2013), 129–158; and Austin Long and Brendan Rittenhouse Green, “Stalking the Secure Second Strike: Intelligence, Counterforce, and Nuclear Strategy,” Journal of Strategic Studies 38, no. 1–2 (2015).

22 David S. Cloud, “Aboard a U.S. Nuclear Sub, a Cat-and-Mouse Game With Phantom Foes,” Los Angeles Times, September 25, 2015.

23 Wang and Ye, “Lessons for China’s Nuclear Submarine Penetration From the Sino-Japanese Nuclear Submarine Incident” [从中日核潜艇事件看我核潜艇的突防].

24 Tian Jianwei (田剑威), “094 Nuclear Submarine: China’s ‘King of South China Sea’” [094 型核潜艇, 中国 ‘南海之王’].

25 Mcconnaughy, "China’s Undersea Nuclear Deterrent: Will the U.S. Navy Be Ready?” 41–42.

26 Ibid.

27 Kamphausen and Scobell, “Right Sizing the People’s Liberation Army: Exploring the Contours of China's Military.”

28 Jordan Wilson, “China’s Expanding Ability to Conduct Conventional Missile Strikes on Guam,” U.S.-China Economic and Security Review Commission, May 10, 2016.

29 Sue-Lin Wong and Ben Blanchard, “U.S. Tells China That Anti-Missile System Not a Threat,” Reuters, July 26, 2016,

30 Li Bin, “China and the New U.S. Missile Defense in East Asia,” Carnegie Endowment for International Peace, September 6, 2012,

31 Admittedly, U.S. experts interpret this U.S. pledge differently. Some believe that the United States intends to defend against both nuclear and conventional Chinese regional ballistic missiles. Others think this statement refer primarily to Chinese conventional missiles. U.S. Department of Defense, “Ballistic Missile Defense Review Report.”

32 Wu Riqiang, “Avoiding Sino-U.S. Inadvertent Nuclear Escalation,” Renmin University, 2016,

33 In the U.S. case, the Ohio-class SSBNs and the converted Ohio-class cruise missile submarines (SSGNs) share the same bases at Kings Bay for the Atlantic fleet and Kitsap (formerly Bangor) for the Pacific fleet.

34 Cao Xiaoguang (曹晓光), “Foundation of Nuclear War: In-Depth Analysis of International Ballistic Missile Nuclear Submarine Bases” [核战基石:深度解读世界弹道导弹核潜艇基地], (Beijing: Aviation Industry Press (航空工业出版社), 2016).

35 Andrew S. Erickson and Lyle J. Goldstein, “China’s Future Nuclear Submarine Force: Insights from Chinese Writings,” Naval War College Review 60, no. 1 (Winter 2007).

36 Long and Green, “Stalking the Secure Second Strike: Intelligence, Counterforce, and Nuclear Strategy”; and Benjamin B. Fischer, “Canopy Wing: The US War Plan That Gave the East Germans Goose Bumps,” International Journal of Intelligence and Counterintelligence 27, no. 3 (2014).

37 Author’s private discussions with former U.S. senior officials and experts, January 2018.

38 Wang and Ye, “Lessons for China’s Nuclear Submarine Penetration From the Sino-Japanese Nuclear Submarine Incident” [从中日核潜艇事件看我核潜艇的突防], 34-41.

39 Zachary Keck, “China’s ‘Dangerous Intercept’ of US Spy Plane,” Diplomat, August 23, 2014.

40 Thom Shanker, “China Harassed U.S. Ship, Pentagon Says,” New York Times, March 10, 2009.

41 “Underwater Drone Incident Demonstrating Three Deeper Themes: U.S. And China Entering ‘New Battlefield’” [潜航器事件藏三大暗线 中美步入‘新战场’], DW News (多维新闻), December 20, 2016,

42 There are debates among some Chinese experts about whether China should continue to rule out a nuclear response if its nuclear ICBMs (such as the silo-based DF-5) were struck by conventional precision-strike weapons.

43 “Preliminary Analysis on Why China Has Not Established a Missile Nuclear Submarine Operational Patrol Mechanism” [浅谈中国为何从未建立过导弹核潜艇战备巡航制], Sina Military, 2016. It is necessary to note that there are some exceptions. For example, U.S. SSBNs do sometimes make publicly announced port calls to foreign countries.

44 “Suspected Newest 094a Strategic Nuclear Submarine of the Chinese Navy Was Revealed” [疑似中国海军最新094a战略核潜艇首次曝光], Sina Military,; “DF-21D May Be Put on Nuclear Submarines, Can Change the International Maritime Warfare Fundamentally” [DF-21D或装备核潜艇 世界海战模式将有巨变], China Central Television (央视网),

45 Benjamin S. Purser III and Michael S. Chase, “Waypoint or Destination? The Jin-Class Submarine and China’s Quest for Sea-Based Nuclear Deterrence,” Jamestown Foundation China Brief 12, no. 5 (August 3, 2012).

46 Yang Longshu (杨龙塾), Feng Dechao (冯德朝), and Luan Houbin (栾厚斌), “Development of U.S. Nuclear Submarines Against a Background of Strategic Readjustment” [战略调整背景下美国核潜艇的发展], Modern Ships (现代舰船) 5 (2010); Ma Yao (马尧), “‘Underwater Wolves’ Competing in the Waters of the Asia-Pacific; China Urgently Needs to Build Maritime Anti-Missile Network” [‘水下狼群’逐鹿亚太水域,中国亟须打造海上反导网], The Paper,

47 Ronald O'Rourke, “Navy Columbia Class (Ohio Replacement) Ballistic Missile Submarine (SSBN [X]) Program: Background and Issues for Congress,” Congressional Research Service, August 18, 2016.

48 Tian Yu (田聿), “New Strategic Nuclear Submarine Becomes an All-Rounder” [新型战略核潜艇变身‘全能选手’], China National Defense News (中国国防报), May 20, 2016.

49 Ibid.

50 Ibid.

51 Song Zhongping (宋忠平), “Song Zhongping: Future Attack and Strategic Missile Nuclear Submarines Will Be Integrated” [宋忠平:未来攻击型与战略导弹核潜艇将融合], China Central Television 4 (央视网), “Across the Strait,” June 3, 2015,

52 “Deep Analysis: China’s Nuclear Black Fish Shows Up Overseas With National Flag; One Fact Can Not Be Ignored” [深度:中国核黑鱼高举国旗突现海外 一事实不容忽视], Sina Military,

53 Dave Majumdar, “The Navy Needs More Nuclear Attack Submarines (and Congress Is Coming to the Rescue),” National Interest, January 4, 2018.

54 Office of the Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People's Republic of China 2016; Office of the Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People's Republic of China 2017; and Samuel J. Locklear, U.S. Pacific Command and U.S. Forces Korea, Hearing Before the Senate Armed Services Committee, 113th Cong. (2015) (statement of Admiral Samuel J. Locklear, U.S. Navy Commander, U.S. Pacific Command, April 16, 2015).

55 Office of the Secretary of Defense, Annual Report to Congress: Military and Security Developments Involving the People's Republic of China 2017.

56 Shou Xiaosong (寿晓松), The Science of Military Strategy [战略学]; Wang and Ye, “Lessons for China’s Nuclear Submarine Penetration From the Sino-Japanese Nuclear Submarine Incident” [从中日核潜艇事件看我核潜艇的突防]; “Preliminary Analysis on Why China Has Not Established a Missile Nuclear Submarine Operational Patrol Mechanism” [浅谈中国为何从未建立过导弹核潜艇战备巡航制]; Yoshihara and Holmes, “China’s New Undersea Nuclear Deterrent: Strategy, Doctrine, and Capabilities”; and Bell, “The Impact of the Type 094 Ballistic Missile Submarine on China’s Nuclear Policy.”

57 Mcconnaughy, “China’s Undersea Nuclear Deterrent: Will the U.S. Navy Be Ready?”

58 Owen R. Cote Jr., “Phase IV of the Third Battle: ASW and Acoustic Parity: 1980-1990,” in The Third Battle: Innovation in the U.S. Navy’s Silent Cold War Struggle With Soviet Submarines (Boston, MA: MIT Security Studies Program, March 2000). Some other U.S. experts also have made similar assessments about the high demand for large numbers of U.S. SSNs to conduct strategic ASW missions. See, for example, Lyle J. Goldstein and William Murray, “Undersea Dragons: China’s Maturing Submarine Force,” International Security 28, no. 4 (Spring 2004), 183.

59 Cote, “Phase IV of the Third Battle: ASW and Acoustic Parity: 1980-1990.”

60 Ronald O’Rourke, “Navy Virginia (SSN-774) Class Attack Submarine Procurement: Background and Issues for Congress” Congressional Research Service, June 12, 2015.

61 Ronald O’Rourke, “Navy Force Structure and Shipbuilding Plans: Background and Issues for Congress,” Congressional Research Service, May 27, 2016; and Ronald O’Rourke, “Navy Force Structure and Shipbuilding Plans: Background and Issues for Congress,” Congressional Research Service, July 31, 2018.

62 O’Rourke, “Navy Force Structure and Shipbuilding Plans: Background and Issues for Congress.”

63 Loren Thompson, “Submarine Production Poised to Outpace Other Pentagon Programs Through 2030,” Forbes, June 15, 2016,

64 Sydney J. Freedberg Jr., “Navy Seeks to Boost Shipbuilding: Amphibs, Subs, Destroyers,” Breaking Defense, April 7, 2016,