US National Security Advisor Jake Sullivan was in Beijing this week for talks with Chinese Foreign Minister Wang Yi, and high-level military officials, as the US and China try and maintain guardrails on their growing strategic rivalry.

Sullivan's talks on Wednesday with General Zhang Youxiam, vice chairman of China's Central Military Commission, included arrangements to improve communication between both militaries, including between high-ranking commanders. 

The White House said in a statement that the first trip by a US national security advisor to China since 2016 was part of ongoing efforts to "maintain channels of communication to responsibly manage the relationship."

As tension continues between the US and China over issues including Beijing's expansionist moves in the South China Sea and consistent military pressure on Taiwan, avoiding miscalculations that could lead to open conflict is a shared priority.

'A new nuclear age'

However, as China has successfully upgraded its conventional military capabilities over the past decade, concern is growing in Washington over China's rapid expansion of nuclear weapons systems, along with Beijing's potential for collaboration with Russia and North Korea's nuclear arsenals.

Vipin Narang, former acting assistant secretary of defense for space policy, told the Center for Strategic and International Studies (CSIS) in August that US President Joe Biden "recently issued updated nuclear weapons employment guidance to account for multiple nuclear-armed adversaries," in particular, the "size and diversity" of China's nuclear arsenal.

Narang told the think tank in Washington that "we now find ourselves in nothing short of a new nuclear age" being driven by "revisionist nuclear challengers who are uninterested in arms control or risk reduction efforts."

"These challengers' actions have forced us to shift to a more competitive approach," Narang said, emphasizing that the growth of China's nuclear force is a "defining feature" of a new nuclear age.

According to the Arms Control Association, a US-based organization advocating arms control policy, as of 2024, the US "is currently replacing or modernizing nearly every component of its strategic nuclear forces." 

The New York Times reported last week that Biden in March approved a "highly classified nuclear strategic plan," that is focused on building a deterrent to China's nuclear expansion and potential strategic collaboration with Russia and North Korea.

"Growing collaboration and evidence of collusion between them is unprecedented, forcing us to think in new and careful ways about challenges such as escalation dynamics and deterring opportunistic aggression," Narang said, referring to China, Russia and North Korea.

What do we know about China's nukes?

According to a 2023 US Department of Defense report, China currently possesses more than 500 operational nuclear warheads, and that number is expected to double by 2030.

By 2035, the Pentagon estimates the number of China's deployed nuclear weapons will be on par with the US and Russia at around 1,500.

In total, both the US and Russia possess more than 5,500 nuclear warheads, but the majority are either mothballed or retired, waiting for dismantlement.

In 2021, non-governmental researchers revealed that China was constructing around 250 missile silos in the country's northwest. The Pentagon currently assesses that the silos are likely completed and being loaded with missiles, Narang told CSIS in August. 

China first carried out a nuclear test in 1964, and for decades, it maintained a modest stockpile as a "minimum deterrent" under a "no first use" policy. 

Although this doctrine hasn't officially changed, since Xi Jinping became leader in 2012, China has rapidly stepped up modernization and mobilization efforts of its nuclear arsenal.

US officials fear this will enable China to carry out "any plausible nuclear employment strategy," as the former head of the US Strategic Command, Charles Richard, put it in 2021, while characterizing China's growth and modernization of nuclear forces as a "breathtaking … strategic breakout."

That same year, US Secretary of State Antony Blinken said Beijing had "sharply deviated from its decades-old nuclear strategy based on minimum deterrence."

"Compared to the People's Liberation Army's (PLA) nuclear modernization efforts a decade ago, current efforts dwarf previous attempts in scale and complexity," the 2023 Pentagon report said.

Former Pentagon official Narang, who has since returned to academia, told the CSIS that although China is not yet a nuclear peer, "growth in its nuclear arsenal's size and diversity — accompanied by posture changes from regional employment to launch on warning — places it on a trajectory to soon become one."

Containing an arms race

For decades, US nuclear strategy has focused on modernizing and replacing older weapons systems, while cutting back the overall number of warheads, rather than expanding its arsenal.

The only remaining arms control treaty between Russia and the US, called New START, is set to expire in 2026.

Since Moscow launched the war in Ukraine in 2022, there have been no new negotiations on a potential replacement. The treaty, which entered into force in 2011, calls for halving the number of nuclear-capable missiles while limiting the number of strategically deployed warheads to 1,550.

Officially, the Biden administration still embraces pursuing arms control agreements to prevent nuclear proliferation.

Pranay Vaddi, the US National Security Council's senior director for arms control, disarmament, and nonproliferation, told the Arms Control Association in June that the administration has "adjusted our strategy to account for a more complex and worsening security environment but we are in no way abandoning our principles."

However, Vaddi added that "absent a change in the trajectory of adversary arsenals" the US may be required to "increase current deployed numbers" in coming years.

China is not a signatory to any bilateral nuclear arms control agreement.

In June 2023, National Security Advisor Sullivan said the Biden administration would seek to open discussions with China on arms control. Later that year, Mallory Stewart, US assistant secretary of state for arms control, met with her Chinese counterpart, Sun Xiaobo, for arms control talks.

Stewart told the Arms Control Association the talks "led to a lot of questions" on the US side about Chinese proposals for a "no first use" agreement, which she said on the surface appeared inconsistent with China's development of "launch-on-warning capacity."

Although Stewart said the talks were a "constructive step," legally binding risk prevention between the US and China is still a long way off, as there is a "trust deficit" in the current environment.

"China has never been transparent publicly or privately about the size and capability of its nuclear arsenal," Bonnie Glaser, managing director of the German Marshall Fund's Indo-Pacific program, told DW.

"Now that China is modernizing its arsenal and substantially increasing its inventory of nuclear weapons, most observers believe that the Chinese will not agree to engage in talks with the US on nuclear weapons at least until they complete their planned upgrade," she added.

After Sullivan's Beijing talks, Reuters news agency cited an unnamed administration official who stated that there was "limited opportunity" to open a conversation on nuclear weapons, but any progress would continue to be in "fits and starts."

"They've signaled some willingness to start nibbling around the margins of arms control, but then they're not very forward-leaning about following through on that," the official said.

Edited by: Keith Walker