US and Russia Agree to Honor New START Limits Informally After Expiry
The U.S. and Russia have agreed to informally uphold the New START treaty's nuclear limits after its expiration, but without verification measures, raising concerns about future arms control and the evolving nuclear landscape involving China.
The expiration of New START: what it means and what’s next
For the first time in decades, the U.S. and Russia have no limits on nuclear weapons
UN chief warns of ‘grave moment’ as final US-Russia nuclear arms treaty expires
Russia says will act responsibly despite New START nuclear treaty expiry
Cost constraints on the US–Russia strategic nuclear balance after New START
The United States and Russia agreed on Thursday to continue observing the core limits of the New START nuclear arms treaty after its formal expiration, averting—for now—a complete collapse of constraints on the world’s two largest nuclear arsenals.icanw +1 The informal understanding came as the pact, which capped each side at 1,550 deployed strategic warheads and 700 delivery systems, ran out on 5 February after 15 years in force.un +1
The arrangement, described by officials as a pledge to “operate in good faith,” followed last-minute talks in Abu Dhabi and is expected to last at least several months while the two governments explore options for a successor framework.axios +1 Kremlin spokesman Dmitry Peskov said Moscow “regrets” the treaty’s end but remains ready for dialogue if Washington responds “constructively,” while the White House said President Donald Trump will set out his arms‑control plans on his own timeline.npr +2 UN Secretary‑General António Guterres called the expiry a “grave moment,” warning that, for the first time in more than half a century, there are no binding limits on US‑Russian strategic arsenals.un +1
An Informal Deal Without Inspectors or Legal Teeth
The post‑expiry understanding keeps both sides within New START’s numerical ceilings but does not revive its verification regime, including on‑site inspections, regular data exchanges and advance notifications of missile movements.npr +2 Those mechanisms had already been eroding—Russia suspended inspections in 2023 and pandemic disruptions had curtailed visits—but their full loss removes a key buffer against mistrust and miscalculation, experts said.npr +2
Negotiations in Abu Dhabi—reportedly involving U.S. envoys on the sidelines of other talks—produced what one American official described as an agreement “to start a discussion about ways [the treaty] could be updated,” including how to address emerging technologies and missile defence.axios +1 However, any more durable arrangement would require political approval in both capitals, where leaders have clashed over broader security issues from Ukraine to cyber operations, raising doubts about how long voluntary restraint can last. Arms‑control advocates welcomed the move as “better than nothing” but stressed that, without legally binding commitments, either side can walk away at will.russiamatters +1
A Nuclear Order Without Guardrails—and With China Rising
The treaty’s end underscored a broader unraveling of Cold War‑era arms control: with New START gone, every major bilateral US‑Russia limitation regime has now lapsed, from the Anti‑Ballistic Missile Treaty to the INF Treaty.npr +1 Analysts warned that the vacuum could fuel a medium‑term arms competition, especially if Washington “uploads” additional warheads onto existing missiles or Moscow accelerates deployment of new systems, though both face significant fiscal and industrial constraints.iiss +1 The International Institute for Strategic Studies estimated U.S. nuclear‑force spending near $950 billion over the next decade, while Russia’s war‑strained budget limits rapid expansion.iiss
The U.S. administration has argued that any future framework must take account of China’s rapidly growing nuclear arsenal, which independent estimates now put at roughly 600 warheads and rising by about 100 per year.iiss +1 Beijing expressed “regret” over New START’s expiration and urged Washington and Moscow to maintain strategic stability, but reiterated it would not join formal disarmament talks until its arsenal is closer to parity.aljazeera +1 That stance complicates U.S. hopes for a trilateral deal and leaves open how to adapt verification and limits to a more multipolar nuclear landscape.cnn +1
The Bigger Picture
The provisional U.S.–Russian decision to keep observing New START’s caps has temporarily slowed fears of an immediate arms race, but it has not replaced the legal and technical scaffolding that underpinned strategic stability for decades.npr +1 With no inspectors in silos, no binding caps and a rising third nuclear power outside the talks, the next months will test whether two rival capitals can convert a fragile gentleman’s agreement into a verifiable regime—or whether the world will drift into an era of unconstrained great‑power nuclear competition.iiss +1