SINGAPORE: The last nuclear treaty between the United States and Russia, the New Start agreement, lapsed on Thursday (Feb 5), ending decades of formal limits on how many nuclear warheads the two powers can deploy.
The pact’s expiry has sparked concerns of a renewed global arms race.
United Nations Secretary-General Antonio Guterres described the moment as a “grave moment for international peace and security” and urged Washington and Moscow to head quickly to the negotiating table.
Russia had offered to extend the agreement, but received no formal response from the US.
CNA takes a look at why Washington appeared reluctant to preserve the treaty – and how China may have factored into its calculations.
What is the New Start treaty?
Signed in 2010 by then US President Barack Obama and his Russian counterpart Dmitry Medvedev, the New Start treaty placed caps on the number of deployed strategic nuclear warheads and the missiles and bombers used to deliver them.
Under the pact, each country was limited to 1,550 deployed nuclear warheads and no more than 700 deployed intercontinental ballistic missiles, submarine-launched ballistic missiles and heavy bombers.
Crucially, the treaty also established a detailed verification regime, including data exchanges and short-notice, on-site inspections, allowing both sides to monitor compliance and reduce the risk of miscalculation.
The inspections, however, were stopped during the COVID-19 pandemic and never resumed.
In 2023, Russian President Vladimir Putin said Russia could not allow US inspections of its nuclear sites when Washington and its NATO allies had openly declared Moscow’s defeat in its war with Ukraine as their goal.
This forced each side to rely on its own intelligence assessments of what the other was doing.
Despite this breakdown, both Washington and Moscow said they would continue to observe the treaty’s numerical limits until its expiration.
The treaty followed a long line of US-Soviet and later US-Russian nuclear arms control agreements dating back to the Cold War, beginning with the Strategic Arms Limitation Talks (SALT I) in 1972.