The New START treaty, the last remaining nuclear arms control agreement between Russia and the United States, expired on February 5, 2026, ending more than half a century of mutual restraints on strategic nuclear arsenals.
This development removes verifiable limits on deployed warheads, missiles, and launchers, raising alarms about a potential new nuclear arms race involving the world’s major powers, including China’s expanding arsenal.
Treaty Expiry and Immediate Consequences
New START, signed in 2010 and extended once in 2021, capped each side at 1,550 deployed strategic nuclear warheads. With its lapse at midnight Prague time (February 5), neither Russia nor the U.S. is bound by these caps or inspection mechanisms. Russia proposed a one-year voluntary extension to allow time for successor talks, but the U.S. under President Trump did not formally respond.
Moscow criticized the U.S. stance as “mistaken and regrettable,” stating both sides are now free to act independently while remaining open to diplomacy for stabilization.
Russia’s Position and U.S. Silence
Russian officials emphasized responsibility, readiness for countermeasures against new threats, and willingness to negotiate a comprehensive framework.
President Putin had floated informal adherence for another year, but Trump made no public statement on the expiry. The White House indicated decisions on arms control would come on his timeline, with interest in a broader deal potentially including China.
China’s Role and Rising Risks
China’s nuclear stockpile, estimated at around 600 warheads (far smaller than the roughly 4,000 each for Russia and the U.S.), continues rapid growth. Beijing has refused trilateral talks, citing its smaller arsenal. Experts warn that the treaty’s end, combined with China’s buildup, could fuel an unconstrained arms race.
Without transparency, predictability erodes, increasing crisis risks—exacerbated by AI, new technologies, and limited communication channels among nuclear states.
Global Alarm and Calls for Action
U.N. Secretary-General Antonio Guterres described the expiry as coming “at a worse time,” with nuclear weapon use risk at its highest in decades.
He urged immediate negotiations for a successor with verifiable limits and risk reduction. Analysts predict both Russia and the U.S. could add hundreds of warheads within a couple of years under worst-case planning. The lapse ends Cold War-era restraint traditions, heightening global instability amid ongoing geopolitical tensions.
This milestone underscores the fragility of nuclear arms control in a multipolar world, with no immediate replacement in sight despite diplomatic openings.