Russia's suspension of its last remaining nuclear weapons treaty with the United States may have dashed any hopes of dragging China to the table to start talking about its own rapidly accelerating nuclear arms programmes.
Regional diplomats and security analysts had held out the prospect of China somehow being convinced to join U.S.-Russian talks on extending the New START arms control treaty ahead of its expiry in 2026 as a way of alleviating growing fears over Beijing's rapid military modernisation.
China's nuclear arsenal sits at the core of those concerns as it grows in size and sophistication - an expansion that the United States recently noted is now gathering pace.
The Pentagon's annual China report released last November noted that Beijing appeared to accelerate its expansion in 2021 and now has more than 400 operational nuclear warheads - a figure still far below U.S. and Russian arsenals both deployed and in reserve.
By 2035 - when the ruling Communist Party's leadership wants its military to be fully modernised - China will likely possess a 1,500 nuclear warhead stockpile and an advanced array of missiles, the Pentagon says.
"Compared to traditional Russian-U.S. exchanges, China is a black box - but one getting bigger every year," an Asian security diplomat said on Wednesday.
"Putin's suspension may have set us further back in terms of getting China to step up to the transparency table. There is so much we need to know about its policies and intentions."
In a speech ahead of the first anniversary on Friday of Russia's invasion of Ukraine, President Vladimir Putin announced Moscow was suspending a treaty signed in 2010 that caps at 1,550 the number of strategic nuclear warheads the United States and Russia can each deploy while providing for mutual inspections.
Analysts said the move could imperil the delicate calculus that underpins mutual deterrence between the two countries, long the largest nuclear powers by far, and spark an arms race among other nuclear states.
Tong Zhao, a U.S.-based nuclear expert at the Carnegie Endowment for International Peace, said he believed Putin's move limits the prospects of U.S.-China nuclear cooperation.
"This is only going to make China even less interested in pursuing cooperative nuclear security with the United States," Zhao told Reuters. "Now even this last example of arms control cooperation is being seriously undermined."
NO FIRST USE
A nuclear power since the early 1960s, China for decades maintained a small number of nuclear warheads and missiles as a deterrent under its unique "no first use" pledge.
That pledge remains official policy but the arsenal that surrounds it has grown rapidly in recent years as part of Beijing's broader military modernization under President Xi Jinping.
The People's Liberation Army now has the ability to launch long-range nuclear-armed missiles from submarines, aircraft and an expanding range of silos in China's interior - a "nuclear triad" that some experts fear could be used, for example, to coerce rivals in a conflict over Taiwan.
The Pentagon also warns of possible conditions over "no first use" as the build-up continues - questions that echo many raised by regional military attaches and security scholars.
"Beijing probably would also consider nuclear use to restore deterrence if a conventional military defeat gravely threatened PRC survival," the Pentagon report notes, using the initials for China's official name.
A month earlier, Washington's Nuclear Posture Review said Beijing is reluctant to engage in strategic nuclear discussions but that both bilateral and multilateral talks are needed.
"The scope and pace of the PRC's nuclear expansion, as well as its lack of transparency and growing military assertiveness, raise questions regarding its intentions, nuclear strategy and doctrine, and perceptions of strategic stability," it said.
Some experts believe Beijing has long been wary of being bound by any three-way talks with Russia and the United States given how far it remains behind U.S. capabilities, at least for another decade or more.
FAILURE TO COMMUNICATE
Academics familiar with once-regular unofficial and semi-official exchanges - so-called Track 2 and Track 1.5 discussions - with Chinese counterparts over nuclear policy say they have dried up over the last five years amid wider political tensions.
Singapore-based strategic adviser Alexander Neill said he believed China might increasingly support Russia's position rhetorically, while feeling emboldened to further accelerate its own build-up.
That would make it harder for the United States and its allies to engage Beijing on its nuclear doctrine, particularly on "no first use".
"China has been consistent in supporting arms control between the U.S. and Russia and has long wanted to maintain the image of being a responsible stakeholder - but there are growing questions about the future," said Neill, an adjunct fellow with Hawaii's Pacific Forum think-tank.
"The aim of the U.S. and its allies is to get crystal clarity over its 'no first use' policy because there's the Taiwan question," he said, referring to the democratically governed island that Beijing sees as its own territory.
Carnegie's Zhao said Putin's announcement might increase the risk of inciting other nuclear powers to expand their nuclear arsenals and break long-held commitments not to stage fresh tests.
"If that happens, it is a very negative development in terms of international ... nuclear order."
(Reporting By Greg Torode in Hong Kong and Martin Quin Pollard in Beijing; editing by Nick Macfie and Mark Heinrich)
