UN Secretary-General António Guterres warned the world is at a “grave moment to international peace and security” as the US‑Russia Strategic Arms Reduction Treaty (New START) expires tonight. He urged the United States and Russia to return immediately to negotiations to agree a successor framework that restores verifiable limits, reduces risks, and strengthens shared security.
Guterres said the treaty’s lapse marks “the first time in more than half a century” without binding limits on the two countries’ nuclear arsenals. He described the expiry as the dissolution of decades of arms control achievement and warned that the risk of nuclear weapon use is now the highest in decades.
The UN noted that the United States and Russia hold the overwhelming majority of the world’s nuclear stockpile. Guterres highlighted how New START had significantly improved security—particularly for the populations of both countries—by building stability, lowering the chance of catastrophic miscalculation, and enabling the removal of thousands of nuclear weapons from national arsenals.
Signed in 2010 by US President Barack Obama and Russian President Dmitry Medvedev, New START limited strategic nuclear forces—those intended to strike an opponent’s political, military and industrial centers. It capped deployed strategic warheads at 1,550 per side, limited deployed intercontinental and submarine‑launched missiles and heavy bombers to 700, and set a maximum of 800 deployed and non‑deployed launchers.
The treaty also created short‑notice on‑site inspections to verify compliance. Those inspections were halted during the COVID‑19 pandemic and effectively suspended after President Vladimir Putin in 2023 paused Russia’s participation in response to US support for Ukraine. Since then, each side has relied on its own intelligence assessments.
With New START expired and no successor talks underway, the UN warned that the lapse ends more than half a century of formal constraints on long‑range nuclear forces. Without binding limits, either Moscow or Washington would be free to increase missile inventories and deploy hundreds more strategic warheads, increasing global danger.
