The End of New START: A Guide to the Lapse of the US-Russia Nuclear Arms Control Treaty and the New Nuclear Reality

On February 5, 2026, the global security architecture crossed a historic threshold. The New Strategic Arms Reduction Treaty (New START)—the last remaining bilateral nuclear arms control agreement between the United States and Russia—officially expired. Its lapse marks the first time since the early 1970s that the world's two largest nuclear powers are operating without legally binding limits on their strategic arsenals.[1][7]

Signed in 2010 by U.S. President Barack Obama and Russian President Dmitry Medvedev, New START was the cornerstone of modern nuclear deterrence. The agreement strictly capped each nation at 1,550 deployed strategic nuclear warheads and 700 deployed delivery systems, which included intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles, and heavy bombers.[1][4]

However, the treaty's true value extended far beyond its numerical ceilings. New START established a rigorous verification mechanism that provided both militaries with unprecedented transparency. This included biannual data exchanges detailing the status of nuclear forces and the right to conduct short-notice, on-site inspections at each other's nuclear bases.[2]

This transparency regime began to fracture well before the treaty's expiration date. In February 2023, amid the fallout from the invasion of Ukraine, Russia suspended its formal participation in New START. Mutual inspection visits and data exchanges ceased, though both Washington and Moscow publicly committed to abiding by the treaty's central numerical limits.[1][6]

By its own legal design, New START could not survive indefinitely. The treaty was drafted for an initial 10-year term with the option for a single five-year extension. That extension was exercised at the final hour in February 2021, setting a hard expiration date of February 5, 2026, unless a completely new framework was ratified.[1][4]

In the months leading up to the deadline, diplomatic efforts to bridge the gap stalled. In September 2025, Russian President Vladimir Putin proposed a voluntary, one-year extension of the treaty's central limits, provided the United States acted in a similar spirit of restraint.[6]

While U.S. President Donald Trump initially indicated that the proposal sounded like a good idea, the administration ultimately declined to formalize a stopgap measure. By January 2026, the U.S. position had solidified around the reality of the expiration, with the administration arguing that the bilateral framework was no longer sufficient for modern security needs.[2][4]

The primary driver behind the U.S. reluctance to simply renew the bilateral status quo is the rapid expansion of China's nuclear capabilities. The Pentagon estimates that Beijing is significantly increasing its operational warhead count, fundamentally shifting the global landscape from a two-power dynamic to a three-power nuclear age.[3]

From the perspective of U.S. defense planners, locking into a treaty that strictly limits American and Russian forces while leaving China's growing arsenal entirely unconstrained is a strategic liability. Consequently, the U.S. has insisted that any future arms control framework must be multilateral.[3][7]

Despite the treaty's lapse, analysts do not expect an immediate, dramatic surge in the production of new nuclear weapons. In the near term, both the United States and Russia are likely to keep their deployed strategic forces relatively close to the former New START ceilings, as maintaining deterrence does not strictly require a massive numerical buildup.[3]

The more pressing risk lies in the technical capacity for "uploading." Both nations possess thousands of non-deployed reserve warheads. Without treaty limits, either side could relatively quickly load these additional warheads onto existing missiles, rapidly escalating the number of deployed weapons during a crisis.[2][3]

Furthermore, the permanent loss of the verification regime forces both militaries to rely entirely on national technical means—such as satellite surveillance and intelligence gathering—to monitor the other's capabilities. Without the certainty provided by data exchanges and inspections, defense planners are naturally pushed toward worst-case scenario modeling.[1][2]

This ambiguity complicates crisis management. When transparency disappears, the pressure to adopt a "launch on warning" posture increases, as leaders may feel compelled to make civilization-altering decisions within minutes based on unverified intelligence estimates rather than established baselines.[2][7]

The expiration also carries profound diplomatic consequences across the globe. Non-nuclear-weapon states, particularly across the Global South, view the collapse of New START as a failure of the United States and Russia to uphold their disarmament commitments under Article VI of the Nuclear Non-Proliferation Treaty (NPT).[1][3]

As the world navigates this new era, the nature of nuclear competition is shifting. Rather than focusing purely on warhead counts, the major powers are directing resources toward advanced delivery systems, hypersonic glide vehicles, artificial intelligence integration, and space-based sensors.[3][7]

For now, global strategic stability relies on informal, unilateral restraint rather than binding international law. The guardrails of the Cold War and post-Cold War eras have been dismantled, leaving a complex, multipolar nuclear reality where deterrence is maintained through ambiguity and technological edge rather than mutual verification.[2][7]