Nuclear Arms Control at a Crossroads as New START Treaty Expires
The landmark New START treaty between the United States and Russia is set to expire on Thursday, , marking the removal of the last remaining mutual limits on the world’s two largest nuclear arsenals. The treaty’s demise arrives at a moment of heightened global instability, raising concerns about a potential unraveling of decades-long efforts to manage and reduce nuclear risks.
Experts warn the expiration represents a significant setback for international arms control, a system that has been steadily eroding in recent years. “When it comes to nuclear risks, everything is trending in the wrong direction over the course of 2025,” said Alexandra Bell, president and chief executive of the Bulletin of the Atomic Scientists. “Nuclear risks have become more complex, more dangerous and we have seen leaders fail in their obligation to manage those risks.”
Bell continued, stating that the expiration of New START is akin to “watching the United States and Russia fritter away half a century of work to maintain nuclear stability between the two largest nuclear states.” The treaty, originally signed in 2010 by then-Russian President Dmitry Medvedev and President Barack Obama, limited each country’s deployed strategic warheads to 1,550 and the total number of delivery systems to 800.
Medvedev, now a vocal advocate for a more assertive Russian foreign policy, echoed the sentiment that the treaty’s expiration should be a cause for global alarm. “When there is an agreement, it means there is trust,” he said, “but when there is no agreement, it means that trust has been exhausted.”
Arms control advocates have made last-ditch appeals for both superpowers to salvage the treaty, but prospects for a quick resolution appear dim. In September, Russian President Vladimir Putin proposed extending New START by one year, a suggestion initially welcomed by former President Donald Trump, who called it “a good idea.” However, those remarks were not followed by substantive negotiations.
Trump, in a recent interview with the New York Times in January, indicated a willingness to pursue a new agreement, but one that included China, which possesses a significantly smaller nuclear arsenal – approximately 600 warheads, with very few deployed for immediate use, according to estimates from the Federation of American Scientists (FAS). By comparison, the FAS assesses the US arsenal at 5,177 and Russia’s at 5,459, including stockpiled and retired warheads.
The pursuit of a trilateral agreement, however, is viewed with skepticism by some analysts. Jennifer Kavanagh, director of military analysis at the Defense Priorities arms control advocacy group, described Trump’s hopes for a “better deal” as “wishful thinking.”
“If the administration thinks getting a new ‘better’ treaty after this one lapses will be easy, they are mistaken,” Kavanagh said. “An agreement with Russia is… likely a requirement to get China onboard with nuclear arms control. Trump may be the ultimate dealmaker, but in this case he would be better off hanging on to the agreement he has a little longer before trying to get a better one.”
Beyond the numerical limits, New START established a robust system of mutual monitoring, data sharing, and inspections. However, Russia suspended its participation in these verification measures in 2023, citing US support for Ukraine following Russia’s full-scale invasion.
The expiration of New START is occurring against a broader backdrop of arms control agreements collapsing. Agreements limiting missile defense systems, intermediate-range forces, and mutual overflight rights have already been abandoned. Both Russia and the United States have invested heavily in modernizing their nuclear arsenals, and leaders have increasingly employed nuclear rhetoric. Trump has even threatened to end the US moratorium on nuclear tests.
Daryl Kimball, head of the Arms Control Association in Washington, warned that the end of New START could rapidly ignite a new arms race. “There are many in the nuclear weapons establishment who want to rapidly build up the size of the US force in order to counter China’s strategic buildup,” Kimball said.
The demise of New START also casts a shadow over the 1970 Nuclear Non-Proliferation Treaty (NPT), which aims to prevent the spread of nuclear weapons. The NPT is scheduled for review this year, and the expiration of New START could undermine its credibility. “This would represent a direct violation of the United States’ legal obligations under the NPT, and would shake the foundations of yet another core set of rules undergirding the important, if imperfect, rules-based order,” Kimball explained.
Some analysts argue that nuclear deterrence, the theory that nuclear weapons prevent large-scale conflict, is losing its effectiveness. Alex Kolbin, a nuclear weapons analyst, recently wrote in the Bulletin of the Atomic Scientists that “nuclear weapons are no longer functioning as a decisive factor in global security,” particularly in the wake of the war in Ukraine and increased tensions between Russia and NATO.
The situation underscores a growing concern that the international security landscape is becoming increasingly unpredictable and dangerous, with the potential for miscalculation and escalation rising as the constraints of arms control agreements disappear.
