The end of nuclear arms control
For the first time in more than 50 years, no agreement is now in force limiting the number of strategic nuclear warheads deployed by the world’s two atomic superpowers. The New Start treaty, which capped deployed warheads at 1,550 each, was allowed to lapse on Thursday with no replacement — though Russia’s Vladimir Putin had offered America’s Donald Trump a one-year extension. By removing other safeguards, the expiry makes the world more dangerous. It raises the prospect, too, not just of a new US-Russia arms race but a free-for-all that pulls in non-nuclear powers.
The most immediate practical loss is New Start’s verification regime. This included on-site inspections, data exchanges and notifications of movements of missiles or bombers. After the Ukraine war began, Russia suspended these in February 2023; the US later followed suit. But there is now no easy way for the provisions to snap back even if, say, a Ukraine peace is agreed.
This raises the risks of mistakes or miscalculations. It also makes it all the more dangerous that the US and Russia could quickly increase deployed warheads above the 1,550 limit, even without manufacturing new ones. Either could take bombs from their extensive stockpiles and add them to existing multi-warhead missiles and bombers. Without inspections, neither side will be able to see if the other is doing so. The end of the treaty means there is no legal or diplomatic redress if one side suspects the other; the only option would be to deploy more warheads in pursuit of parity. This was the logic of the original US-Soviet arms race in the days before arms control.
Any US-Russian build-up would have knock-on effects. China, a fast-emerging nuclear power that the Pentagon estimates has 600 warheads and is on course for 1,000 by 2030, might feel compelled to accelerate its own build-up. Seeing Russia and America abandon legal caps and expand their arsenals could also prompt others to follow suit, especially as Trump has raised doubts over the US commitment to use its nuclear “umbrella” to protect allies. Experts fear countries, including Turkey and Saudi Arabia, might seek nuclear status.
The US president has repeatedly insisted that any future arms control framework must include China; the US military fears it will soon face a heavy numerical disadvantage against a combined Chinese-Russian arsenal. Without mentioning China on Thursday, however, Trump said that rather than extending the “badly negotiated” New Start it was better to work on a “new, improved, and modernized Treaty”.
Seeking to bring in China makes sense, although Beijing reiterated last week that since its arsenal remained much smaller it would “not participate in negotiations at this stage”. Russia has said that a deal that brought in China should also include the UK and France. But the US president would have set a better example to Beijing, and the rest of the world, by agreeing with Russia to roll over New Start while starting talks on a successor treaty. This would have strengthened Washington’s hand in trying to engage China in potential first steps towards future arms limits, such as data exchange and monitoring.
Beijing, too, should realise that neither a costly and perilous US-Russia arms race — leaving China with a bigger gap to close — nor nuclear proliferation are in its interests. Engaging with Moscow and Washington could help to constrain those risks. But with Russia and the US accounting for almost 90 per cent of the global stockpile, the first priority is for these two countries to return to mutually agreed limits. Allowing the last legal safeguard to lapse is a big step in the wrong direction.