The United States and Russia are on the verge of entering their first unrestrained nuclear arms race since the Cold War unless a last-minute agreement is reached before the New START treaty expires on Feb. 5. Its end would remove all formal limits on the world’s two largest nuclear arsenals, marking a historic rupture with more than half a century of arms control designed to prevent catastrophe.
New START, signed in 2010, is the final surviving pact governing long-range nuclear weapons. Without it, there would be no legal caps on deployed warheads or delivery systems for the first time since landmark agreements were signed in 1972 during a thaw between Washington and Moscow. Those Cold War-era treaties were born out of fear that unchecked competition could trigger either a devastating misunderstanding or a financially ruinous arms buildup.
Russian President Vladimir Putin has proposed extending existing limits for one year to allow time for negotiations on a successor agreement. U.S. President Donald Trump has not formally responded, saying last month that “if it expires, it expires,” while arguing any replacement should be broader and better. Some U.S. lawmakers and analysts urge rejecting the offer, saying Washington needs freedom to expand its arsenal to counter China’s rapid nuclear growth.
Trump has said he wants to pursue denuclearization talks involving both Russia and China, but Beijing has dismissed that idea as unrealistic, noting that its arsenal remains far smaller than those of the other two powers. China currently has an estimated 600 nuclear warheads, with Pentagon projections suggesting the total could exceed 1,000 by 2030, all outside any arms control framework.
Arms control experts warn that without a treaty, both Washington and Moscow would be forced to plan based on worst-case assumptions about the other’s weapons development. Treaties like New START not only limit numbers but also require transparency and data sharing, channels seen as essential to reducing suspicion and avoiding miscalculation during crises. Without them, analysts say, an arms race could become self-sustaining and deeply destabilizing.
Replacing New START would be especially difficult. Russia has developed new nuclear-capable systems, including hypersonic weapons and underwater torpedoes, that fall outside the treaty’s scope. The United States, meanwhile, has announced plans for a space-based missile defense system that Moscow views as an attempt to undermine strategic balance. These developments complicate efforts to craft a comprehensive new agreement.
In Washington, debate is intensifying over whether to maintain limits or expand U.S. forces. A bipartisan congressional commission warned in 2023 that the United States faces an “existential challenge” from two nuclear peers simultaneously and recommended preparing to redeploy warheads previously removed under New START. That could involve restoring warheads to existing missiles and returning dozens of strategic bombers to nuclear roles, steps former officials say could be done without building new weapons.
Some analysts estimate the United States could roughly double its deployed warheads if it chose to do so, while Russia could add hundreds of its own, though significant changes would take many months. Arms control advocates counter that such moves would fuel a costly and dangerous competition. The Congressional Budget Office estimates the United States will spend nearly $1 trillion between 2025 and 2034 just to modernize and operate its nuclear forces under current plans.
Critics of expansion warn that exceeding New START limits would prompt Russia to respond in kind and encourage China to accelerate its buildup. They argue more weapons would not make the world safer and could heighten the risk of miscalculation. Supporters of a tougher stance say Russia can no longer be trusted, pointing to Moscow’s suspension of treaty inspections in 2023 over U.S. support for Ukraine.
Russian officials say they are prepared for any outcome. Dmitry Medvedev, the former president who signed New START, described Trump as unpredictable and warned that any new threats to Russia’s security would be met decisively. With days remaining before the treaty’s expiration, the future of nuclear arms control hangs in the balance, and the path chosen could shape global security for decades to come.
