The US and China re-engage on arms control. What may come next

For more than six decades, the United States has been worried about China’s regional influence, military activities—and its nuclear potential. For instance, in 1958, US officials considered using nuclear weapons to thwart Chinese artillery strikes on islands controlled by Taiwan, according to a document leaked by Daniel Ellsberg in 2021. Now, as then, a nuclear conflict between the United States and China would be devastating for both sides and the world.

The United States has a decades-long experience of nuclear arms control and strategic stability talks with the Soviet Union, and later Russia. However, there has not been a sustained bilateral dialogue between Washington and Beijing on how to reduce the risk of conflict, nuclear escalation, and nuclear arms control and disarmament. Until recently, China had rebuffed US overtures for bilateral talks on nuclear risk reduction and arms control, and on other security issues.

Adding to the tensions, China has embarked since the early 2000s on a major buildup of its relatively smaller nuclear arsenal and has resisted calls for a global halt on the production of fissile material for nuclear weapons. In response, some current and former national security insiders, as well as many in Congress, suggest that the US arsenal “should be supplemented” to add more capability and flexibility to counter two “near-peer” nuclear adversaries. In other words, the potential for an unconstrained, three-way arms race is growing.

But things started to change on November 6 with the meeting in Washington between US Assistant Secretary of State for the Bureau of Arms Control, Verification and Compliance Mallory Stewart and China’s Ministry of Foreign Affairs Director-General of Arms Control Sun Xiaobo.

A modest yet important breakthrough. The US-Chinese discussion on arms control—the first of its kind since 2018—was described by the US side as a “candid and in-depth discussion on issues related to arms control and nonproliferation.” According to the State Department’s readout of the meeting, “the United States highlighted the need to promote stability, help avert an unconstrained arms race, and manage competition so that it does not veer into conflict.” The Chinese Foreign Ministry’s readout also said the “[t]he two sides had an in-depth, candid and constructive exchange of views” on nuclear weapons matters, as well as an exchange on “regular arms control.”

Several participants told me that the meeting was “wide-ranging” and “positive in tone,” but that it did not involve much substantive exchange of views on the issues, which is not surprising. Tangible progress will require time and sustained give-and-take from both sides.

The next step, ideally, will be for Presidents Joe Biden and Xi Jinping, who are set to meet this week, to direct their teams toward concrete nuclear risk reduction and arms control measures that enhance mutual security.

More nuclear capabilities imply more responsibilities. The Pentagon recently estimated that China has a stockpile of approximately 500 nuclear weapons, whereas independent researchers estimate that China’s nuclear forces may have a total of up to 410 operational warheads available for deployment on approximately 210 strategic delivery launchers, which include intercontinental ballistic missiles and submarine-launched ballistic missiles.

China’s arsenal is not only growing (it had less than 200 nuclear warheads in 2000), but it is also diversifying and modernizing. It is now well-documented that China has started to deploy new solid-fueled missiles that can be launched more quickly than its older liquid-fueled missiles. Beijing is also increasing the number of its long-range missiles that are armed with multiple warheads, constructing three new intercontinental ballistic missile silo fields near the cities of Yumen, Hami, and Ordos, and continues to improve its sea-based nuclear force.

The Chinese government has not acknowledged these new developments, let alone explained their rationale. But, to many, Beijing is likely responding to what it perceives as threatening changes in US nuclear strategy—introduced in the 2018 Nuclear Posture Review of the Trump administration and not undone by the 2022 Nuclear Posture Review of the Biden administration. These changes have lowered the threshold for US nuclear weapons use and called for improvements in US military capabilities that could be used to potentially destroy or significantly degrade China’s nuclear forces. China’s buildup should be understood as effort to augment China’s nuclear retaliatory forces so they can more reliably withstand a potential US first strike—nuclear or conventional—in the event of a conflict over Taiwan.

China’s growing and diversifying nuclear arsenal indicates that it can no longer sit on the nuclear arms control and disarmament sidelines.

China is, of course, not a stranger to the global nuclear nonproliferation and risk reduction system. Beijing has joined multilateral nuclear weapons-related agreements, including the Nuclear Non-Proliferation Treaty (NPT) and the Comprehensive Test Ban Treaty (CTBT). It is an active participant in the annual dialogues involving the NPT’s five recognized nuclear-armed states on nuclear doctrines and terms, known as the “P5 Process,” which is currently chaired by Russia. But China’s refusal to engage in nuclear arms control diplomacy runs afoul of its obligation under Article VI of the NPT to “pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament.”

Chinese leaders—and UK and French leaders alike for that matter—have been very leery about engaging in talks to limit their nuclear arsenals, citing their relatively smaller nuclear forces. China has also emphasized its long-standing policy of unconditional “no first use”—the only nuclear-armed country to have such policy. Beijing claims to support nondiscriminatory disarmament and minimum deterrence, and in recent years Chinese officials have argued they will engage in the nuclear arms control only after US and Russian leaders achieve deeper cuts in their much-larger nuclear arsenals. In June 2023, Washington embassy spokesperson Liu Pengyu stated that “China’s nuclear strength is far from being on par with the United States and Russia. The time is not ready yet for [Beijing] to join the nuclear arms control negotiations proposed by some.”

Of course, China’s nuclear arsenal is still modest by comparison to the US and Russian arsenals, each of which are about nine times larger than China’s. But China’s nuclear modernization efforts could have significant strategic implications that make it even more important for the “Big Three” (the United States, Russia, and China) to pursue meaningful progress on nuclear arms control to avoid a destabilizing and dangerous nuclear arms race.

Toward a more serious, sustained dialogue. In response to China’s nuclear buildup, US officials—Republicans and Democrats alike—have prioritized engagement with China in talks to identify measures to reduce nuclear risks and prevent destabilizing and costly strategic weapons competition.

In 2020, the Trump administration tried to do so by publicly challenging China’s leaders to engage in a three-way arms control negotiation with the United States and Russia. Disappointingly, although not so surprisingly, this attempt was a failure. The move also even jeopardized the future of the US-Russian treaty that limits their deployed long-range nuclear forces (New START), which was extended until 2026 by Presidents Biden and Vladimir Putin only days before it was due to expire in February 2021.

Since arriving in office, President Biden and his administration vowed to “pursue arms control to reduce the dangers from China’s modern and growing nuclear arsenal,” but it only recently began to spell out how it sought to do so.

On June 2, in an address to an Arms Control Association forum, National Security Advisor Jake Sullivan reiterated the Biden administration’s “willingness to engage in bilateral arms control discussions with Russia and with China without preconditions.”

Sullivan followed up his speech with talks with China’s Foreign Minister Wang Yi first in Malta in September and then in Washington in October. These diplomatic efforts apparently paved the way for the November 6 meeting on arms control between US and Chinese officials Stewart and Sun.

Sullivan’s June 2 address provides some important clues about the types of issues the US side likely raised in the arms control talks. Sullivan suggested that the United States and China, along with the other NPT nuclear-armed states, could engage in new nuclear arms control and risk reduction efforts such as establishing more robust crisis communications channels and “formalizing a missile launch notification regime” for all five permanent members of the UN Security Council—the United States, Russia, China, the United Kingdom, and France. “It’s a small step that would help reduce the risk of misperception and miscalculation in times of crisis,” Sullivan added.

These suggestions don’t happen in a vacuum: The United States and Russia have a ballistic missile launch notification agreement already in place, and Russia and China have their own bilateral agreement too.

In his remarks, Sullivan also called for talks on “maintaining a ‘human-in-the-loop’ for command, control, and employment of nuclear weapons” to reduce the risk of miscalculation in a crisis. This would require that the US and China—and other nuclear-armed states—agree to pursue technical discussions designed to reach common understandings on how the use of artificial intelligence, particularly high-risk, cutting-edge deep learning models, can be banned or at least limited so the use of nuclear weapons is effectively kept under human control. This proposal seems to have reached the highest level with Presidents Biden and Xi reportedly discussing limits on the employment of artificial intelligence in the control and deployment of nuclear weapons.

In future meetings, US and Chinese diplomats should go one step further and set out a process for formulating a joint understanding that cyberwarfare capabilities will not be used to try to interfere with other states’ nuclear command and control systems, which could also severely alter decision-making in a crisis.

Sullivan also suggested that all five capitals commit to “transparency on nuclear policy, doctrine, and budgeting,” an implicit but clear reference to the US concern and interest in understanding the rationale for China’s nuclear buildup. This suggests a strong US interest in the negotiation of a common system for reporting on respective nuclear weapons holdings, a concept China has long resisted.

On November 7, a senior US official reportedly told Reuters that “the Chinese delegation did not respond substantively” to issues Sullivan raised, including a US need for a better understanding of Beijing’s nuclear weapons doctrine, policies, and budget. “I wouldn’t say we learned anything new from them or that they delved into a great amount of detail in terms of their own nuclear force, their buildup and whether or not their policy or doctrine could be shifting over time,” the official said.

China may be more open to talks on nuclear doctrine than on arms control, given China’s stated commitment to a “no first use” policy and its concern with the US policy that leaves open the option to use nuclear weapons first in a conflict.

From talks to concrete actions. Further down the road, an even more ambitious approach that might be considered in the multilateral, nuclear-five setting would be for Washington and Moscow to propose that China, France, and the United Kingdom freeze the size of their nuclear stockpiles so long as the United States and Russia maintain the current limits on their strategic arsenals—even after New START expires—and make good faith efforts to negotiate deeper verifiable reductions in their stockpiles.

As Sullivan emphasized on June 2, “the United States does not need to increase [its] nuclear forces to outnumber the combined total of [its] competitors to effectively deter them.” With respect to Russia, he said: “It is in neither of our countries’ interests to embark on an open-ended competition in strategic nuclear forces—and we’re prepared to stick to the central limits [of New START] as long as Russia does. And rather than waiting to resolve all of our bilateral differences—the United States is ready to engage Russia now to manage nuclear risks and develop a post-2026 arms control framework.”

Considering the difficulty of achieving a new bilateral nuclear arms control framework, the United States and Russia could seek an executive agreement or simply a reciprocal unilateral arrangement verified with national technical means of intelligence that commits the two sides to respect New START’s central limits until a more permanent and comprehensive nuclear arms control arrangement is concluded.

As Presidents Biden and Xi are meeting this week in San Francisco on the margins of the Asia-Pacific Economic and Cooperation forum, they can and should seize this opportunity and agree to continue their nascent bilateral nuclear arms control dialogue.

With US-Russian relations at rock bottom, the Kremlin still waging its war on Ukraine, and the last remaining treaty limiting US and Russian strategic nuclear arsenals set to expire in early 2026, the risk of nuclear escalation and a nuclear arms race with Russia is already too high. That makes it all the more important for Xi and Biden to direct their team to work harder and more steadily to reduce tensions and head off the possibility of a costly, dangerous, unconstrained three-way nuclear race that no one can win.