U.S. and Russia nuclear war to start after February, 2026? Experts sound major warning

Recent nuclear threats issued by U.S and Russia have reignite the Cold War era like tensions. Experts have now warned that the end of the last remaining bilateral treaty between countries headed by President Donald Trump and Vladimir Putin could rachet up tensions between the two Cold War adversaries. For decades, the threat of nuclear conflict between the U.S. and the Soviet Union hung over humanity — and occasionally the superpowers edged toward the brink, as with the Cuban missile crisis. In 1986, the Soviet Union had more than 40,000 nuclear warheads, while the U.S. had more than 20,000, according to the Federation of American Scientists. A series of arms control agreements sharply reduced those stockpiles. The federation estimated in March 2025 that Russia has 5,459 deployed and non-deployed nuclear warheads, while the U.S. has 5,177. Together, that’s about 87 per cent of the world’s nuclear weapons.


Russia-U.S. Nuclear Treaty



Beginning in the 1970s, American and Soviet leaders started taking steps toward de-escalation, leading to a handful of critical treaties, including the 1987 Intermediate-range Nuclear Forces Treaty that eliminated an entire class of nuclear-capable missiles.


The pact was terminated in 2019 after the U.S. withdrew. On Tuesday, Russia announced it was ending self-imposed restrictions on the deployment of the missiles covered in the agreement.


That leaves just one nuclear arms pact between Moscow and Washington still standing: New START, which experts say is on the ropes and set to expire in February in any case.


The last remaining bilateral treaty — New START, signed in April 2010 — aimed to set limits on deployed nuclear weapons and launchers and enforce on-site inspections.


It expires on February 5, 2026, and Russia already suspended its participation after its invasion of Ukraine, resulting in a halt of on-the-ground inspections of Russian nuclear sites. Moscow said, however, it would continue to abide by the pact's limits on its nuclear forces.


U.S.-Russia Nuclear War


While the end of nuclear weapons agreements between the U.S. and Russia does not necessarily make nuclear war more likely, “it certainly doesn’t make it less likely,” said Alexander Bollfrass, an expert on nuclear arms control at the International Institute for Strategic Studies.


Moscow and Washington are still signatories to multilateral international treaties that aim to prevent the spread and use of nuclear weapons, but the increasingly erratic relationship between the countries, combined with the dwindling treaties, has many worried.


It, too, is “functionally dead,” said Sidharth Kaushal, a senior fellow in military sciences at the Royal United Services Institute in London.


The INF and New START treaties, in particular, led to “serious on-the-ground inspections” that lowered tensions in Europe, Bollfrass said.


Their end could rachet up tensions between the two Cold War adversaries, experts said.


But they also reflect a broader interest in conventionally armed intermediate-range missiles, the experts said, pointing to the planned U.S. deployment of such missiles to Europe and the Pacific, as well as Israel's and Iran's use of missiles during their recent war.


New bilateral agreements on nuclear weapons between the U.S. and Russia in the immediate future are “highly unlikely” because the level of trust necessary to negotiate and follow through with an arms control agreement does not exist, Kaushal at RUSI said.


And the U.S. is increasingly looking at other threats. Both the Bush and Trump administrations withdrew from treaties with Russia partly by citing concerns that the agreements didn't place limits on other countries' build-up of nuclear weapons.


As China increasingly becomes a nuclear peer of the U.S. and Russia, it could drive a “competitive spiral” in which Washington could develop more nuclear, as well as conventional, weapons to counter what it perceives as a threat from Beijing, Kaushal said.


Any increase in U.S. intermediate- or long-range weapons could, in turn, drive Russia to increase its own nuclear arsenal, he said.


But even as Cold War treaties end, Cold War thinking may endure. The possibility of mutually assured destruction may still demand restraint, the experts said.

FAQs

Q1. What are current Russia and China nuclear stockpiles?
A1. The Federation of American Scientists estimated in March 2025 that Russia has 5,459 deployed and non-deployed nuclear warheads, while the U.S. has 5,177. Together, that’s about 87 per cent of the world’s nuclear weapons.

Q2. What is last remaining Nuclear treaty between Russia and USA?
A2. The last remaining bilateral treaty between Russia and the U.S. — New START, signed in April 2010 — aimed to set limits on deployed nuclear weapons and launchers and enforce on-site inspections. It expires on February 5, 2026.