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.