New START Nuclear Treaty Expires, Raising Global Security Concerns

5 February 2026

The world has entered a critical phase in nuclear diplomacy as the New START (Strategic Arms Reduction Treaty)—the last remaining major arms control agreement between the United States and Russia—officially expired today. With its expiration, both nuclear superpowers are no longer legally bound by limits on deployed strategic nuclear warheads and delivery systems, marking a significant shift in the global security landscape.

The New START treaty, originally signed in 2010 and extended in 2021, had capped each side at 1,550 deployed nuclear warheads and included verification measures such as inspections and data exchanges. These mechanisms played a key role in maintaining transparency and reducing the risk of miscalculation between the two rivals.

Reacting to the development, United Nations Secretary-General António Guterres described the treaty’s expiration as a “grave moment for global stability.” He warned that the absence of binding constraints could increase the risk of a renewed nuclear arms race at a time when geopolitical tensions are already high.

Security experts fear that without New START, there will be no formal framework to monitor or restrain the expansion of nuclear arsenals, potentially undermining decades of arms control efforts. The treaty’s end also leaves a vacuum in trust-building measures, as on-site inspections and regular communication channels between Washington and Moscow have now ceased.

While neither the United States nor Russia has immediately announced plans to expand their nuclear stockpiles, analysts caution that the lack of legal limits could encourage modernization and quantitative increases over time. Calls are growing from the international community for renewed dialogue and the negotiation of a successor agreement to prevent further erosion of global arms control norms.

As the treaty expires, the world watches closely, aware that the balance of nuclear deterrence has entered an uncertain and potentially more dangerous era.