A Nuclear World Without Guardrails: Landmark Treaty Expires, Raising Fears of New Arms Race
The final binding limit on U.S. And Russian strategic nuclear weapons expired at midnight GMT on , ushering in a new era of uncertainty and escalating concerns about a renewed global arms race. The New START treaty, signed in 2010, capped each side’s deployed strategic nuclear warheads at 1,550 and imposed limits on delivery systems like intercontinental ballistic missiles and heavy bombers.
United Nations Secretary-General António Guterres warned that the expiration represents a “grave moment” for international peace and security. “For the first time in more than half a century, we face a world without any binding limits on the strategic nuclear arsenals” of the United States and Russia – the two countries that together hold the vast majority of the world’s nuclear weapons, Guterres said in a statement issued on .
The treaty’s demise removes decades of established verification measures, including data exchanges, notifications, and on-site inspections, designed to reduce mistrust and prevent miscalculation. These tools, built upon a foundation of arms control agreements dating back to the Cold War, played a crucial role in preventing catastrophe and reducing global nuclear stockpiles, according to Guterres.
While the U.S. And Russia will no longer be bound by upper limits for their strategic nuclear arsenals, Russia has pledged to act responsibly, while also warning it will take “decisive” measures if its security is threatened. Washington has not announced plans to adhere to the treaty’s limits beyond the deadline.
The expiration of New START also occurs against a backdrop of increasing global tensions and the expansion of nuclear capabilities by other nations. China, while still lagging behind the U.S. And Russia in the number of warheads, is rapidly expanding its nuclear arsenal and is projected to have over 1,000 nuclear weapons by 2035, up from around 200 in 2019.
Former Under Secretary of State for Arms Control Rose Gottemoeller suggested that allowing the parameters of the treaty to continue without formal renewal for a year could be a viable option. However, the broader implications extend beyond simple numbers.
Experts note that New START was the last thread in a fabric of nuclear diplomacy woven over the past half-century. This fabric included not only limits on weapons but also avenues for communication, data sharing, and building confidence between Washington and Moscow. The aim was to minimize the risk of nuclear war stemming from misunderstanding or miscalculation.
The situation is further complicated by Russia’s breach of international consensus regarding the use of nuclear weapons, with President Vladimir Putin hinting at deploying tactical nuclear weapons in the war in Ukraine. These “low yield” weapons, despite their designation, can still carry a payload more powerful than the bombs dropped on Hiroshima and Nagasaki.
President Trump has indicated a desire for a wider nuclear deal that includes China, but Beijing has rejected this idea, arguing that the U.S. And Russia – possessing 90% of the world’s more than 12,000 nuclear warheads – should reduce their forces first. Trump also previously suggested lifting the three-decade moratorium on nuclear weapons tests.
The expiration of New START raises concerns about the future of arms control and the potential for a new era of instability. The treaty’s collapse underscores the importance of rebuilding the political fabric of nuclear diplomacy, a process that will require significant effort and a renewed commitment to dialogue and cooperation.
Pope Leo XIV recently exhorted the U.S. And Russia to avert a new arms race, stating, “It is more urgent than ever to replace the logic rooted in fear and mistrust with a shared ethic … Toward the common good.”
