Last bilateral arms pact nears end - New START faces Feb. 5 deadline

New START, the last remaining legally binding arms-control treaty between the United States and Russia, is set to expire on Feb. 5, 2026, raising fresh concerns about strategic stability, verification and the future of global non-proliferation diplomacy. Its lapse would remove decades of formal caps on long-range nuclear forces at a time of heightened geopolitical tension and accelerating nuclear programs elsewhere.

Signed in 2010 and in force since 2011, the treaty constrained the two countries’ strategic arsenals with widely cited limits: 1,550 deployed strategic nuclear warheads and controls on delivery systems, variously described in official summaries as a cap of 700 deployed delivery systems and an 800 total-launcher ceiling, of which 700 may be deployed. The agreement also created a robust verification regime with on-site inspections, continuous data exchanges, government notifications on missile tests and weapons movements, and a Bilateral Consultative Commission to resolve technical and political questions.

That verification architecture has been weakened in practice. In February 2023, President Vladimir Putin suspended Russia’s participation in the treaty and the United States followed suit, ending mutual inspection visits and data exchanges. U.S. State Department annual reports cited in recent analyses say Washington has “not detected any Russian breakout from the treaty’s central limits,” but those same reports over the past three years have warned that Russia’s refusal to permit on-site inspections has prevented the United States from confirming compliance with the warhead limit.

Security analysts and multilateral institutions warn the loss of transparency will increase uncertainty and could incentivize worst-case planning. The Nuclear Threat Initiative states that “New START’s expiration marks the removal of caps on U.S. and Russian long-range nuclear forces for the first time in decades,” and that the loss of data exchanges and the Bilateral Consultative Commission “opens the door for worst-case scenario planning and misunderstandings that fuel uncontrolled arms races.” A research associate at the International Security Programme at Chatham House put the diplomatic stakes bluntly: “This would mark a significant break in more than five decades of bilateral nuclear arms control. It would also signal a move away from nuclear restraint, making the world a more dangerous place.”

Proponents of keeping the treaty point to its practical and fiscal benefits. Extending New START has been framed as protecting U.S. security while reducing the incentive for expensive force expansions; advocacy groups have summarized the case as “Extending New START protects the United States and saves billions.” Experts say the pact’s transparency has also reduced the chance of misperception. Monica Duffy Toft of The Fletcher School said, “By providing transparency into the world’s two largest nuclear arsenals, New START has lowered the risk that either side will misinterpret normal military activity as preparation for a nuclear strike.”

The treaty’s potential expiry also carries diplomatic consequences ahead of the 2026 Nuclear Non-Proliferation Treaty Review Conference. Observers say the disappearance of the last U.S.-Russia arms-control accord without a replacement would weaken the disarmament signal nuclear-weapon states should present at the RevCon and could deepen divides between nuclear and non-nuclear states.

Policymakers retain options short of letting a vacuum take hold. Analysts note that even if New START expires, “there are steps that can reduce risk and prevent a complete collapse of nuclear restraint,” though those measures would require urgent political will and new or ad hoc transparency arrangements if formal limits are not renewed.