The last major arms control agreement between the United States and Russia — the New START Treaty — officially expired on February 5, 2026, ending the final binding limits on deployed strategic nuclear warheads between the two largest nuclear powers.
Signed in 2010, New START capped each side at 1,550 deployed strategic warheads, while also mandating regular on-site inspections, data exchanges, and other verification measures to build transparency and reduce the risk of miscalculation.
With the treaty now lapsed, no legally binding numerical limits or mandatory inspection mechanisms remain in place between Washington and Moscow.
Although both countries still maintain roughly comparable overall stockpiles — approximately 4,000 warheads each according to independent assessments — the absence of the treaty removes the legal ceiling and the structured transparency that helped stabilise the strategic balance for over 15 years.
US officials argue that the expiration marks more than a bilateral setback. They contend that the global nuclear landscape has fundamentally changed due to China’s rapid and sustained expansion of its nuclear arsenal.
Beijing is modernising and enlarging its forces at an unprecedented pace, including new intercontinental ballistic missiles, submarine-launched systems, and bomber capabilities. Estimates suggest China could possess over 1,000 warheads by the early 2030s, with further growth projected.
In response, senior US policymakers insist that any future arms control framework must be trilateral — involving the United States, Russia, and China — and include robust, verifiable, and enforceable provisions.
They argue that a bilateral US-Russia deal, even if revived, would no longer be strategically sufficient in a world where a third major nuclear power is actively building up without any constraints.
The deterioration had already begun well before the formal expiry. Russia suspended participation in on-site inspections in 2022, citing tensions related to the Ukraine conflict, and both sides accused each other of non-compliance in recent years.
Washington now maintains that the old Cold War-era model of bipolar arms control is obsolete. A new agreement, they say, must reflect today’s multipolar nuclear reality and include China to remain meaningful and effective in preserving strategic stability.
Without such a trilateral, verified framework, officials warn, the risk of unchecked nuclear competition — and potential escalation — will continue to grow.
The expiry of New START underscores the urgent need for fresh diplomacy in an increasingly complex and dangerous nuclear era.
