New START Treaty Expires, Ending U.S.-Russia Nuclear Limits Amid Arms Race Concerns
The expiration of the New START treaty between the U.S. and Russia ends legally binding nuclear arms limits, raising concerns about a renewed arms race and increasing global security risks amid rising tensions and China's nuclear expansion.
Last Russia-US treaty on nuclear arms control set to expire
UN chief warns of ‘grave moment’ as final US-Russia nuclear arms treaty expires
Expiration of U.S.-Russia nuclear weapons treaty sparks concerns of new arms race
New START nuclear treaty expires, removing key constraints on Russia and US
New START: Last US-Russia nuclear treaty expires
The last remaining nuclear arms control treaty between the United States and Russia expired on Thursday, ending more than half a century of legally binding limits on the world’s two largest nuclear arsenals and prompting warnings of a new arms race.aljazeera +1 The New Strategic Arms Reduction Treaty (New START), signed in 2010 and extended once in 2021, had capped each side at 1,550 deployed strategic warheads and 700 deployed delivery systems, underpinned by intrusive inspections and data exchanges.stonewall +1
UN Secretary‑General António Guterres called the moment “grave” and said the risk of a nuclear weapon being used was at its highest in decades.un +1 For the first time since the early 1970s, Washington and Moscow now face no verified, treaty‑based limits on their strategic forces.
How New START Ended — and What Each Side Wants Next
New START entered into force in 2011, was fully implemented by 2018, and was extended by five years in 2021, pushing its legal expiry to early February 2026.stonewall The treaty’s detailed verification regime produced more than 300 on‑site inspections and tens of thousands of notifications over its lifetime, giving both sides transparency on each other’s nuclear posture.russiamatters
The architecture began to fray when Russia suspended its implementation in 2023, halting inspections while informally staying under the central limits.stonewall +1 In 2025 President Vladimir Putin proposed that both sides voluntarily observe the caps for one additional year after expiry, but U.S. officials did not accept the offer.russiamatters +1 President Donald Trump, who had long criticized existing arms control, said of the looming deadline, “If it expires, it expires… We’ll just do a better agreement.”reuters +1
Moscow has framed the lapse as Washington’s responsibility but said it would act “responsibly and in a balanced manner,” while also warning of “decisive military‑technical countermeasures” if it perceives new threats.reuters China expressed “regret” at the treaty’s end and urged the U.S. and Russia to resume dialogue, even as it continues to resist joining any binding limits while its own, much smaller arsenal grows.thediplomat +1 NATO and European leaders have urged “restraint,” arguing that the loss of inspections and data exchanges increases the risk of miscalculation on the continent.chosun +1
Rising Risks of a Three‑Way Arms Race
Analysts said the lapse removed a key brake on quantitative buildups just as geopolitical tensions and new weapons technologies were already straining crisis stability.reuters +1 Without New START’s ceilings, both Washington and Moscow could over time deploy hundreds of additional warheads, with experts warning that planners are likely to assume worst‑case scenarios in the absence of verified data.reuters +1
The treaty’s end also came as U.S. intelligence and independent monitors estimated China’s nuclear stockpile in the low‑600s, with some projections suggesting it could approach 1,000 warheads by 2030 if current trends hold.stonewall That trajectory has fueled calls in Washington for a new framework that includes Beijing, even as Chinese officials argue they should not be bound by the same thresholds as far larger U.S. and Russian forces.aljazeera A senior analyst at the Stockholm International Peace Research Institute told Reuters that the loss of transparency would make relations among nuclear powers “more crisis‑prone,” underscoring concerns that a three‑way arms race could emerge.reuters
The Bigger Picture
With New START gone, arms‑control advocates describe an “extinction” of the Cold War–era framework that once constrained everything from anti‑ballistic missiles to intermediate‑range systems.globalsecurityreview Experts have floated stop‑gap steps — such as voluntary adherence to previous limits, renewed notifications on major exercises, and incident‑prevention hotlines — while urging longer‑term talks on a successor deal that can accommodate a nuclear triangle and emerging technologies.russiamatters +1 Whether Washington, Moscow and Beijing choose restraint or rearmament will shape global security for decades to come.