Modernizing Without Destabilizing: China’s Nuclear Posture in a New Era

Since its first nuclear test in 1964, China has maintained a very restrained nuclear capability and nuclear posture. This restrained nuclear development is a result of China’s traditional nuclear thinking, which focuses on a lean and effective nuclear deterrent. Compared with the U.S. and Russian history of an intensive nuclear arms race, China’s moderate nuclear development and deployment has contributed to regional strategic stability. That said, the development of new technology around the world and the evolving security environment have presented new challenges for China to maintain its credible nuclear second-strike capability. Western nuclear thinking has also started to influence the Chinese view of nuclear strategy and policy. Given these complicating factors, what are the options for Chinese decisionmakers to maintain a credible nuclear deterrent while simultaneously ensuring China’s nuclear modernization will not unnecessarily destabilize the regional security environment? This paper will first analyze both recent developments in China’s nuclear policy and their potential impact on regional strategic stability, and then offer policy options that both protect China’s security interests and continue to contribute to regional stability.

Nuclear Retaliation: When and How

From the very beginning, China’s leaders have limited the role of Chinese weapons to retaliating against a nuclear strike, and therefore they have served to deter nuclear strikes in the first place. In its official nuclear strategy, Chinese nuclear weapons have no role to play in any other scenarios. As Chinese defense white papers have repeatedly stated, the mission of the country’s nuclear forces is to “deter other countries from using nuclear weapons against China, and to conduct nuclear retaliation.”¹ Chinese leaders also seem to believe that, for the purpose of nuclear deterrence, Chinese nuclear weapons do not need to be kept on high alert during peacetime. It is believed that China separates its nuclear warheads from missiles during peacetime,² and the alert level will only be raised when a security crisis emerges.³ Even if China were hit by a nuclear attack, it would not necessarily seek an immediate nuclear retaliation. Rather, it might be willing to wait for days or weeks before retaliating.⁴ This policy of delayed retaliation leaves sufficient time for decisionmakers to confirm the nuclear attack and develop an appropriate response.

This is very different, however, from the U.S. and Russian practice of keeping some strategic nuclear weapons on high alert all the time. Since the Cold War era, the United States and the Soviet Union/Russia have sought to maintain strategic early warning capabilities. Early warning systems typically consist of satellites and land-based radars that enable the two countries to detect an incoming missile attack before the warheads explode over their territory. Concerned that the other country might launch a surprise nuclear first strike, both countries are ready to launch their nuclear missiles as soon as they detect an attack in order to ensure that their nuclear retaliation is effective. This defense posture is called Launch on Warning (LOW) or Launch Under Attack (LUA) and has started to influence some Chinese experts’ thinking on when and how their nuclear retaliation should be delivered.

In recent years, China has become more interested in a strategic early warning capability. Some Chinese experts draw inspiration from U.S. and Russian practices and point out that “military powers around the world are all making a strategic early warning system the focal point of their national strategic capability, and therefore are speeding up its construction.”⁵ The same thinking may have been embraced by the government as official policy. In a 2015 defense white paper, China for the first time pledged to “improve strategic early warning” for its nuclear forces.⁶ That pledge appeared again in its 2019 defense white paper.⁷ Within the military, some have started to argue for China to adopt the LOW posture.⁸ The 2013 edition of the Science of Military Strategy states that “when the conditions are ripe and necessary, and if we can indeed confirm that the enemy has launched nuclear missiles against us, we can quickly launch nuclear missiles in retaliation, before the enemy’s warheads reach and detonate over the targets to cause real damage to us.”⁹ Given that the launch of nuclear retaliation by China would happen shortly after the launch of a first nuclear strike by the enemy, the authors argue that this posture would not change China’s long-standing unconditional no first use (NFU) of nuclear weapons principle.

But even if the NFU policy would not be undermined, shifting from a posture of delayed retaliation to a LOW posture would constitute a significant change in China’s nuclear operations. Even if China only readies its nuclear missiles for LOW during a crisis, the time window for Chinese leaders to make a decision about nuclear retaliation would be very small and therefore entail many risks. Previously, Chinese leaders could wait until they could confirm that China had experienced a nuclear attack before deciding on retaliation. They could also use this time to confirm the origin country, the scale, and other characteristics of the attack. Such information would be very helpful for deciding if, how, and against whom a nuclear retaliation should be conducted. Under LOW, however, Chinese leaders would have just several minutes to decide whether to launch a nuclear retaliation—before the incoming missiles had even landed. This very short time might not even be enough to verify the authenticity of the alarm, let alone to decide the proper scale and target of the retaliatory attack. To a certain extent, the LOW posture undermines the decisionmaker’s ability to make a proper choice on retaliation based on the specific security environment and battlefield situation. Instead, it pushes nuclear retaliation closer to becoming an almost automatic knee-jerk reaction. As a result, the risk increases of accidental or mistaken nuclear escalation.

Moreover, the Chinese nuclear modernization program has been developing under the assumption that China’s nuclear forces should be able to ride out a first strike and maintain the ability to deliver a nuclear retaliation that is beyond the “unacceptable level of damage.” As a large portion of Chinese land-based missiles become mobile and the country starts to deploy submarine-launched ballistic missiles, China should be more and more confident of its capability to conduct an “assured retaliation,” even after absorbing a first strike. Therefore, shifting from a posture of delayed retaliation to a LOW posture would not further increase China’s nuclear deterrence in a significant manner.

There may be many other reasons why China wants a strategic early warning system, including the ability to order the emergency evacuation of nuclear weapons and to intercept incoming missiles after China acquires an effective missile defense capability. However, given the security risk and the relatively small benefit, China should be very cautious about adopting a LOW posture, even if it obtains a strategic early warning capability in the future.

Nuclear Ballistic Missile Submarines: Avoiding Destabilizing Strategies

Because of concern over the credibility of a largely land-based nuclear deterrent, China has made great efforts to add a sea leg to its nuclear forces. Since the launch of its nuclear submarine program, China’s development of a sea-based nuclear capability has been greatly influenced by the practices of the other major nuclear weapons states. China officially decided to start building nuclear submarines in 1958,¹⁰ only four years after the United States launched its first nuclear submarines and one year after the Soviet Union. During the Cold War, land-based ballistic missiles were prioritized over the nuclear submarine and submarine-launched ballistic missile (SLBM) programs. But after China’s economy began to grow quickly, China began to allocate more resources to the nuclear submarine and SLBM programs, and considerable progress has been made since then. According to official U.S. estimates and open-source research, China has deployed four 094-class nuclear ballistic missile submarines (SSBNs), China’s second-generation SSBN, and is building two more. Each 094 submarine is equipped with twelve JL-2 SLBMs. China is also developing its next-generation 096-class SSBN and JL-3 SLBM.¹¹ This emerging capability is going to be increasingly important for China’s overall nuclear deterrent. But with this growing capability, China also faces a wide range of new challenges.

First, the United States and China have no mutual understanding of how to incorporate China’s new sea-based nuclear capability into the bilateral strategic stability relationship. Through the 2010 Nuclear Posture Review Report and Ballistic Missile Defense Review Report, the Obama administration made commitments to maintaining strategic stability with China. In theory, this means the United States will not deliberately seek to undermine China’s nuclear retaliation capability. Many American and Chinese experts agree that maintaining a relationship of mutual vulnerability should be tacitly accepted as the starting point for discussing broader strategic security issues like missile defense and conventional hypersonic weapons. This mutual understanding, however, does not seem to have been extended to cover the underwater domain. The U.S. Navy, trained during the Cold War to keep enemy SSBNs in the crosshairs, views China’s emerging strategic nuclear submarine fleet as a new threat and has taken measures to develop a counter-capability. Together with allies in the region, the United States has deployed an increasing number of advanced anti-submarine maritime aircraft and nuclear attack submarines to military bases close to China. There are also new research and development programs that seek to use new technologies such as unmanned underwater vehicles to track and trail Chinese submarines.¹² Such tracking and trailing of Chinese nuclear submarines would be necessary if the U.S. Navy wanted to be able to sink them when needed. There is no doubt that China sees such behavior as highly threatening.

Technical and geographical factors further restrain China’s strategic nuclear submarine operations. Current Chinese SSBNs may not be sufficiently quiet to escape enemy detection in the deep sea. As a result, they may have to be deployed primarily in coastal waters in the near term, where the shallow water and noise created by busy shipping traffic can help conceal otherwise noisy submarines. To implement this deployment strategy, China may need to follow the Soviet example of creating a so-called submarine bastion in a certain area of its coastal water. This requires the deployment of substantial anti-submarine warfare (ASW) and general-purpose naval capabilities to sanitize a body of water and make it safe for SSBNs to conduct patrols. This type of operation would be very resource-intensive: during the Cold War, the Soviet Navy devoted a very large portion of its entire assets to protecting its SSBNs. But this is not the most challenging part of the mission.

If the United States seeks to challenge China’s SSBNs, the risk of a conventional military confrontation would rise considerably. This is the most challenging part of China’s SSBN operations. Due to geographical constraints, China may have to deploy most of its SSBNs in the South China Sea and may need to create an SSBN bastion within part of that sea. Doing so would be particularly difficult in the South China Sea because of its busy international shipping traffic and the presence of multiple countries’ naval vessels that make frequent transit within the sea. The United States, with its long-standing commitment to freedom of navigation, is unlikely to stop challenging China’s efforts to keep foreign military vessels out of parts of the South China Sea. As China increases its nuclear submarine operations there, we have already seen several dangerous encounters between U.S. anti-submarine platforms and the Chinese military.¹³ Therefore, even though China’s deployment of strategic nuclear submarines is solely intended to strengthen its nuclear deterrent and has little conventional military utility, it could have significant implications for military tensions and stability at the conventional level. This problem will continue to exist and even grow if the two countries cannot reach a mutual understanding on the implications of China’s SSBN patrols and on how the United States should react to these Chinese operations.

To mitigate the potential risks, it is important for U.S. political leaders to recognize that conducting aggressive anti-submarine operations against Chinese SSBNs does not benefit U.S. strategic interests or U.S.-China bilateral strategic stability. As part of China’s overall nuclear deterrent, Chinese SSBNs do not pose new threats to the security interests of the United States or its allies. For China’s part, there are also options that it can take to minimize the potential destabilizing impact of its SSBN deployment. For instance, China does not need to keep many SSBNs at sea at all times. Unlike the United States, China can choose to keep its SSBN patrol frequency no higher than the level that is necessary to maintain machine and crew proficiency. It would be helpful for China to have a thorough domestic debate about whether it needs to maintain a so-called continuous-at-sea deterrent. Given that China does not face an existential threat during peacetime, China can afford to only deploy its SSBNs to sea periodically during peacetime and when a security crisis emerges. With lower patrol frequencies, the risk of an accident would also be reduced.

China’s practice of maintaining a low alert level for its nuclear forces has been regarded as a positive contribution to strategic stability. With the introduction of SSBNs, however, some suspect that China may not be able to keep its nuclear weapons at low alert level during peacetime. This concern stems from the mainstream practice by other major nuclear powers of keeping their SLBMs ready to launch on strategic nuclear submarines. China does not have to adopt this same practice. In fact, China does not have to conduct patrols with SLBMs or their warheads onboard the submarines during peacetime. As long as potential enemies cannot tell if the submarines are actually equipped with missiles and warheads, the deterrent effect of such patrols would not be negatively affected. With China’s underground submarine facilities at Hainan, China can train its SSBN crews to quickly upload missiles and/or warheads without being detected when a crisis emerges. Given the fact that there have been multiple serious accidents with SSBNs at sea that had major consequences,¹⁴ such a policy of patrolling without missiles or warheads during peacetime would reduce security risks and contribute to stability.

Before China deployed strategic nuclear submarines, it had just a few dozen land-based intercontinental ballistic missiles that could reach the continental United States.¹⁵ Now, with the introduction of SSBNs, the number of Chinese nuclear warheads that can reach the United States may increase considerably. This raises U.S. concerns. The gradually growing size of China’s SSBN fleet and the resulting growth of its overall nuclear stockpile have increased international concern that China is seeking a substantial nuclear expansion.¹⁶ To assuage these concerns, China could choose a development strategy that keeps a modest capability, limits the fleet size to a reasonable number, and at the same time maintains a credible sea-based nuclear deterrent. This can be done by focusing on maintaining a robust shipbuilding infrastructure and training enough reserve crews. Because any significant change to the strategic security environment will take several years, if not longer, to develop, China can afford to maintain a small SSBN fleet in peacetime that can be expanded within a reasonable timeframe when a new strategic threat emerges. This could help avoid the overspending of precious naval resources and still ensure that China has a sufficient SSBN fleet and credible nuclear deterrent.

Managing Conventional and Nuclear Interaction

For decades, China has maintained a relatively clear distinction between conventional and nuclear weapons. It rejects the notion that nuclear weapons should play any role in a conventional conflict and pledges never to use nuclear weapons first under any circumstances.¹⁷ This unconditional NFU principle is unique to the Chinese nuclear strategy. Research shows that Chinese decisionmakers do not think it is credible or morally justifiable to threaten first use of nuclear weapons, and they only need nuclear weapons to play one role: deterring nuclear strikes against China.

The diving line between nuclear and conventional weapons is, however, eroding. This poses a new challenge for Chinese nuclear policy. With the emergence of new military technology, nuclear weapons may become vulnerable not only to nuclear strikes but also to conventional strikes; or at least this is how many Chinese experts see the impact of conventional precision-strike weapons. Some conventional hypersonic weapons, in particular, travel at a speed greater than Mach 5 and can strike targets with exceptional accuracy. China worries that the United States might seek to strike Chinese nuclear weapons or associated command-and-control systems without explicitly crossing the nuclear threshold. Because of these concerns, some Chinese analysts already question the wisdom of China’s decision to stick to the unconditional NFU policy.¹⁸ This only represents a minority view and does not appear to have influenced official policy, but the perception of an increasing threat from conventional weapons to China’s nuclear deterrent is forcing China to face a new reality in which the interaction between conventional and nuclear weapons becomes more complicated.

The termination of the Intermediate-Range Nuclear Forces (INF) Treaty removes obstacles for the United States to develop medium- and intermediate-range ballistic and cruise missiles. The United States also has several programs to develop hypersonic missiles. Some Chinese experts believe that hypersonic missiles are not too cost-prohibitive to be built in large numbers.¹⁹ Therefore, the U.S. argument that they can only be built in small numbers and used as a “niche” capability does not reassure China.²⁰

China itself is also moving at full speed to develop hypersonic technology. The first challenge that this hypersonic competition brings for China is how it should utilize this new technology. Given that hypersonic missiles are more capable of penetrating certain missile defense systems than traditional ballistic missiles, the temptation to use hypersonic missiles as nuclear weapon delivery vehicles may be significant. Believing that Russia and some other countries have been developing hypersonic missiles to be armed with nuclear warheads,²¹ some Chinese experts emphasize the fact that if armed with nuclear warheads, the “high penetration capability and great responsiveness” of such weapons will considerably enhance a country’s capability to “deal with the enemy’s missile defense threat.”²²

It is unknown whether a decision has been made about whether to arm China’s future hypersonic weapons with nuclear warheads or with conventional warheads only. However, future decisions need to ensure that the employment of hypersonic technology will not negatively affect China’s security interests or destabilize the nuclear relationship between China and other nuclear powers. Both the United States and Russia retain a LOW posture and are ready to launch a nuclear retaliation when their early warning system detects an incoming missile strike. The flight trajectories of hypersonic missiles are different from ballistic missiles, but if China possesses both nuclear-armed and conventionally armed hypersonic missiles, the United States may have serious difficulty figuring out whether the incoming missiles they face are part of a nuclear or conventional strike. It is therefore possible that the United States might misunderstand the nature of an incoming Chinese attack and launch a nuclear retaliation against China when China has actually fired conventionally armed hypersonic missiles. If this happens, China will be the victim of a mistaken nuclear strike. Several years ago, the United States decided to give up a plan to convert some of its nuclear submarine-launched ballistic missiles to conventional missiles as part of the Conventional Trident Modification program. The reason for doing so was precisely to avoid any confusion—from an enemy’s perspective—about the nature of a missile strike.²³ This is something that China can draw lessons from.

A second way to reduce the potential impact of conventional hypersonic weapons on nuclear stability is to promote an explicit commitment from nuclear weapons states not to attack nuclear forces with conventional weapons. In the near future, conventional hypersonic weapons may only have a limited capability to strike and destroy nuclear weapons.²⁴ However, Chinese concerns about the United States actually contemplating a conventional first-strike strategy grew when American participants in U.S.-China nuclear Track II dialogues inquired how China would respond if its nuclear forces were hit with conventional weapons. The U.S. inquiry was mainly aimed at understanding the credibility of China’s NFU policy, but was interpreted by some Chinese participants as a veiled threat to China’s nuclear deterrent capability from advanced conventional weapons.²⁵

Such perceptions of a threat from a conventional first strike do not help stabilize the nuclear relationships among major powers, and need to be addressed. As a first step toward that, all nuclear weapons states—including China—could promote a joint commitment to banning the use of conventional weapons against each other’s nuclear capability. Admittedly, there will be challenges regarding the verifiability of such commitments. But even a political commitment that explicitly renounces the option of a conventional first strike against nuclear weapons will contribute to reducing exaggerated concerns. Given the fact that India and Pakistan were able to agree not to attack each other’s nuclear facilities more than twenty years ago, there is little reason why the major nuclear weapons states cannot do the same.

Since the demise of the INF treaty in 2019, the United States has sought to deploy land-based conventional medium- and intermediate-range missiles in the Asia-Pacific region to counter China’s so-called anti-access, area denial (A2AD) capabilities. Such deployment, if implemented, may cause new concerns in China about the survivability of its small nuclear forces, as those U.S. land-based missiles deployed near China could enhance the American capability to execute a conventional counterforce strike against Chinese nuclear forces, including China’s road-mobile nuclear missile launch vehicles. The Chinese government has strongly protested this U.S. policy and is putting political pressure on some U.S. Asian allies to discourage them from allowing the introduction of U.S. land-based medium- and intermediate-range missiles to their countries. However, to address the negative impact of the demise of the INF on regional stability, in addition to the measures discussed above, the United States and China should actively explore options to avoid a missile arms race in the Asia-Pacific theater. The United States should consider limiting its new missile deployment in return for China agreeing to cap the buildup of its regional missile forces. The two countries should also conduct a comprehensive study on how conventional/nuclear dual-capable missiles and nuclear missiles that are not externally distinguishable from their conventional models may create opportunities for misjudgment and risks of inadvertent escalation during a crisis.²⁶

Maintaining a Limited Role for Nuclear Weapons

Since its first nuclear explosion in 1964, China has chosen to maintain a very small nuclear arsenal. One of the consequences of that choice is that China does not feel it can make the numbers and locations of its nuclear weapons transparent. China fears that a higher degree of transparency might negatively affect the survivability of its small nuclear arsenal and therefore undermine the credibility of its nuclear deterrent.²⁷ Its relatively low level of nuclear transparency makes China vulnerable to international criticism, and also presents an obstacle to some confidence-building measures.

That said, China has been very transparent about the conditions under which it will or will not use nuclear weapons. With its unconditional NFU policy, China minimizes the importance of nuclear weapons in its overall national security strategy. This has set a positive example for all other nuclear-capable countries, because none of them has a strict policy of only using nuclear weapons in retaliation to a nuclear attack. When the Obama administration came to power in 2009, the White House also promised to reduce the role of nuclear weapons, but such efforts face growing challenges. More conservative officials and experts have doubted the wisdom of reducing the importance of nuclear weapons, and their suspicion only grows as America’s edge of conventional military superiority is eroding. Many argue that it is time to stop reducing the importance of nuclear weapons and instead raise it.²⁸ Indeed, the administration of President Donald Trump has declined to follow the policy of the previous administration, which sought to make deterring nuclear war the sole purpose of U.S. nuclear forces. In 2018, it also introduced more ambiguous language to its Nuclear Posture Review report regarding the conditions under which the United States may use nuclear weapons. In these circumstances, it is particularly important that China both continues to resist the practice of having nuclear weapons play a more significant role in national security, and helps move the international consensus toward de-emphasizing rather than re-emphasizing the importance of nuclear weapons.

China’s view on the role of nuclear weapons stems largely from its perception that the humanitarian consequences of their use are too overwhelming to make them a justifiable means of warfare.²⁹ This particular attention to the humanitarian consequences of nuclear weapons affects China’s nuclear thinking and has contributed to its decision to maintain a small nuclear arsenal and very restrained nuclear posture.³⁰ It is also very much in line with the main appeal of the recent international movement that calls for awareness of the humanitarian impact of nuclear weapons. China also believes that the most effective way to promote nuclear disarmament is to start by banning the use of nuclear weapons.³¹ Therefore, China can and should more proactively promote its value that the role of nuclear weapons should be restricted and minimized. China can lend more support to efforts by the international community to ban the use of nuclear weapons. This is where the country can play a leadership role and make a contribution to nuclear arms control and international stability.

This text is an updated version of a chapter of the Russian-language book “A Polycentric Nuclear World.”

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