The First Unconstrained Moment in Decades
On February 5, 2026, the New Strategic Arms Reduction Treaty (New START) expired, leaving the United States and Russia without legally binding limits on their strategic nuclear forces for the first time since the early 1970s. For more than five decades, successive arms control agreements placed ceilings on nuclear warheads and delivery systems while creating predictability through verification and data exchanges. With New START’s expiration and no successor in place, those guardrails are gone.
In a letter to President Donald Trump and Secretary of State Marco Rubio, a group of Senate and House lawmakers led by Jeff Merkley warned that the absence of legally binding limits on U.S. and Russian strategic forces increases the risk of renewed nuclear competition and strategic instability. That concern reflects the treaty’s core purpose: reducing incentives for arms racing and lowering the chance of miscalculation.
What New START Did and Why It Mattered
Signed in 2010 and entering into force in 2011, New START capped each country at 1,550 deployed strategic nuclear warheads and limited deployed and non-deployed launchers to 800, with no more than 700 deployed intercontinental ballistic missiles, submarine-launched ballistic missiles, and heavy bombers. Beyond numerical limits, the treaty established extensive verification measures, including on-site inspections and regular data exchanges.
These mechanisms mattered as much as the caps themselves. Inspections allowed each side to confirm the other’s declared forces, while notifications reduced uncertainty about routine military movements. Even after Russia suspended participation in inspections in 2023, U.S. officials reported Moscow remained below the treaty’s limits through its expiration, as reflected in State Department compliance reporting.
How the Treaty Ended Without Replacement
New START’s expiration was not sudden. The treaty was extended once in 2021 for the maximum five years permitted under its terms. Negotiations on a successor, however, failed to produce results. In September 2025, Russian President Vladimir Putin publicly indicated a willingness to continue observing New START limits for one year if the United States formally agreed to do the same. No reciprocal, time-limited understanding was reached, and the treaty expired without replacement.
Without a treaty, the United States must rely primarily on national technical means such as satellite imagery to assess Russian forces. While valuable, those tools do not provide the same level of confidence or transparency as on-site inspections.
Bipartisan Roots of Nuclear Arms Control
For decades, support for nuclear arms control transcended party lines. Republican and Democratic administrations alike negotiated agreements with the Soviet Union and later Russia during periods of intense geopolitical rivalry. Treaties such as SALT, START I, and New START reflected a shared understanding that mutual restraint reduces nuclear danger even when broader relations are strained.
Public opinion has largely mirrored that bipartisan tradition. Polling summarized by the Nuclear Threat Initiative shows overwhelming voter support for negotiating agreements that maintain or reduce current nuclear limits.
Why the Absence of Limits Raises Risk
The absence of legally binding limits does not automatically trigger an arms race, but it removes structural barriers that previously restrained competition. Without caps, both sides face incentives to hedge against worst-case assumptions about the other’s capabilities. Without binding limits, both countries can add more nuclear warheads onto missiles they already possess, expand their forces to hedge against worst-case assumptions, and operate in a strategic environment where misjudgments during crises become more likely.
Arms Control Amid the War in Ukraine
Any discussion of renewed U.S.–Russia nuclear diplomacy now occurs against the backdrop of Russia’s invasion of Ukraine. Lawmakers supporting arms control have stressed that pursuing nuclear risk reduction does not legitimize Russia’s actions. Instead, it addresses a separate and existential concern: preventing miscalculation or escalation between nuclear-armed states.
This distinction has long been part of U.S. arms control policy. Successive administrations treated nuclear agreements as tools to protect the American public and global stability, regardless of other disputes. That logic remains relevant in 2026, when the consequences of failure are potentially catastrophic.
What Comes Next
Several options have been suggested for managing strategic nuclear risk in the wake of New START’s expiration. One is a political understanding under which the United States and Russia would agree to continue observing New START’s limits while negotiating a follow-on agreement.
Another is a new bilateral treaty that updates verification mechanisms and includes emerging technologies not fully covered by New START. Some analysts go further, proposing multilateral arms control frameworks that would include additional nuclear-armed states, though experts caution that bringing others into a single agreement presents significant political and structural challenges.
Why This Moment Matters
For more than half a century, U.S. nuclear policy rested on the premise that verifiable limits reduce the risk of catastrophe. The expiration of New START marks a departure from that framework. Whether the United States and Russia can construct a new system of restraint will shape nuclear risk for decades.
The stakes are not abstract. Without constraints, uncertainty grows, incentives shift, and the margin for error narrows. Reestablishing limits will not solve broader geopolitical conflicts, but it remains one of the few tools capable of reducing the most severe risks facing the world today.
