The agreement between the United States and Russia that restricted their strategic nuclear weapons deployment has lapsed, raising uncertainties about the future plans of President Donald Trump and President Vladimir Putin. The termination of the New START treaty, which was part of a long-standing series of nuclear arms control agreements between Washington and Moscow since 1972, marks the absence of a formal cap on the world’s two largest nuclear arsenals for the first time in over five decades.

While there is a divergence of opinions on whether the end of the treaty will trigger a new nuclear arms race, experts generally concur that significant revisions are necessary to reflect the current nuclear landscape, especially considering China’s expanding weapons program. However, the prospect of a swift agreement among Trump, Putin, and Chinese President Xi Jinping for an updated treaty seems optimistic at best.

Former U.S. diplomat Thomas Countryman, who previously served as acting under-secretary of state for arms control and international security, warned that the risk of a nuclear attack is now at its highest level since the Cuban Missile Crisis in 1962. Countryman expressed concerns over the treaty’s expiration, emphasizing the need for vigilance.

The expired treaty had imposed limits on the U.S. and Russia, restricting them to a maximum of 1,550 nuclear warheads each and placing caps on their intercontinental and submarine-launched ballistic missiles and launchers. Despite Russian President Putin hinting at renewing the treaty before a summit with Trump, the proposal never materialized. Trump has dismissed the significance of the treaty’s expiration, asserting his intention to negotiate a new, improved, and modernized agreement.

U.S. Secretary of State Marco Rubio downplayed the treaty’s end, stressing the importance of involving China in future arms control efforts due to its substantial and rapidly growing nuclear stockpile. The Pentagon reported China’s ambitions to increase its nuclear warheads from approximately 600 to over 1,000 by 2030, signaling a significant nuclear expansion.

Efforts are underway between the U.S. and Russia to maintain the weapon limits of the New START treaty without a formal extension, although uncertainties persist following the treaty’s official expiration. The evolving dynamics in nuclear diplomacy pose challenges and uncertainties as the global community navigates a potentially more unsettled international landscape.