UN Secretary-General António Guterres warned the world faces a “grave moment to international peace and security” as the US-Russia Strategic Arms Reduction Treaty (New START) expires tonight.
“For the first time in more than half a century, we face a world without any binding limits on the nuclear arsenals of Russia and the United States,” Guterres said, urging both countries to return to negotiations immediately to agree on a successor framework that restores verifiable limits, reduces risks, and strengthens common security. He called the treaty’s expiry the dissolution of decades of achievement and said the risk of nuclear weapon use is the highest in decades.
The UN noted that the United States and Russia possess the overwhelming majority of the global nuclear stockpile. Guterres said New START had drastically improved security for all people, especially populations of the two countries, and that Cold War and post‑Cold War arms control helped prevent catastrophe by building stability and reducing the potential for devastating miscalculation. Most importantly, he said, the treaty helped facilitate the removal of thousands of nuclear weapons from national arsenals.
Signed in 2010 by US President Barack Obama and then‑Russian President Dmitry Medvedev, New START limited strategic nuclear weapons — those designed to strike an opponent’s vital political, military and industrial centres. It capped deployed strategic warheads at 1,550 per side, limited deployed intercontinental and submarine-launched missiles and heavy bombers to no more than 700, and set a maximum of 800 deployed and non‑deployed launchers.
The treaty also established short‑notice, on‑site inspections to verify compliance. Those inspections were halted during the COVID‑19 pandemic and were effectively suspended after President Vladimir Putin in 2023 suspended Russia’s participation in response to US support for Ukraine. Since then, each side has had to rely on its own intelligence assessments.
With New START expired and no successor talks underway, the treaty’s lapse marks an end to 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 numbers and deploy hundreds more strategic warheads, the UN warned.
