The New Strategic Arms Reduction Treaty expired this month. The end of New Start is a watershed moment in American nuclear strategy. Far from a failure of diplomacy, this expiration is an overdue correction of a strategic mistake that left America vulnerable to two nuclear rivals: Russia and China. After years of unilateral restraint, while our adversaries expanded their arsenals, America can finally build a nuclear deterrent for the threats we face.
Consider the scale of Russia's nuclear buildup. According to unclassified Defense Intelligence Agency estimates, Moscow maintains approximately 1,550 deployed strategic warheads and up to 2,000 nonstrategic warheads. These figures likely understate reality given Russia's warhead production rates. Vladimir Putin's history of arms-control violations made clear that he wouldn't be constrained by New Start's now-defunct limits -- despite his empty assurances that he would.
But raw numbers tell only part of Russia's story. Moscow has also developed what it calls "novel" nuclear delivery systems, including an ICBM-mounted hypersonic glide vehicle, a nuclear-powered cruise missile, and a nuclear-capable autonomous underwater system. In 2025 the Defense Intelligence Agency warned that Russia believes a "satellite capable of carrying a nuclear device" could "deter Western adversaries reliant on space and enable Russia to disrupt or destroy Western satellites should deterrence fail."
If Russia's modernization were our only challenge, we might manage with the legacy approach of bilateral arms control. But the strategic earthquake reshaping global security is the emergence of China as a second nuclear peer -- one expanding its arsenal at an unprecedented pace.
China's nuclear stockpile has surpassed 600 operational warheads as of mid-2024, and it remains on track to exceed 1,000 by 2030. This isn't incremental modernization. This is a fundamental transformation from a minimal deterrent to strategic parity with America and Russia in both quality and quantity.
The good news is that America is taking action. Last year Congress approved significant additional funding for nuclear modernization. But more must be done. Here are six steps:
- First, we should reconvert missile tubes on our ballistic-missile submarines. New Start required the Navy to convert submarine missile tubes, making them inoperable. As Ohio-class ballistic missile submarines enter dry dock for maintenance, these tubes should be reconverted to increase the most survivable leg of our nuclear triad.
- Second, we must put multiple warheads back on U.S. land-based ICBMs. To stay below New Start limits, America reduced the load on our ICBMs to one warhead per missile. We should load existing Minuteman III ICBMs to their full capacity and ensure that Sentinel ICBMs are also deployed at full capacity. This will provide needed targeting flexibility and increase the value of the most ready and responsive leg of our triad.
- Third, we must accelerate plutonium pit production and eliminate single points of failure in the National Nuclear Security Administration complex.
- Fourth, we must restore our theater nuclear capabilities. This means completing the nuclear-armed sea-launched cruise missile program, forward-deploying additional U.S. tactical nuclear weapons to Europe and the Pacific, and developing hypersonic nuclear-capable delivery systems.
- Fifth, we must change how we think about nuclear modernization. Not everything needs to be a decade-plus program. The Defense Department and the National Nuclear Security Administration, through the Nuclear Weapons Council, should take advantage of our national laboratories and approach nuclear modernization like a rapid capability office.
- Finally, the Energy Department needs to reverse the taboo against testing. Both Russia and China have conducted supercritical nuclear weapons tests exceeding the zero-yield standard. They're also testing novel delivery systems. The bureaucratic foot-dragging has to end so that America can do the same.
Critics will raise predictable objections. To those worried about cost: Deterring nuclear war is far cheaper than fighting one. To those who ask why we should spend so much on weapons we'll never use: We use our nuclear deterrent every single day. The mere existence of a credible nuclear force prevents adversaries from contemplating attacks they would otherwise consider.
And to those who fear an arms race: The race has already begun. Russia and China have been running it for more than a decade while we sat on the sidelines. The question isn't whether there will be competition in nuclear forces, but whether America will show up to compete.
We must plan for a larger, more diverse nuclear arsenal designed for the full spectrum of threats we're likely to face in 2050. With New Start's expiration, we close a chapter written for a different era. We must now write a new one.
Mr. Cotton, a Republican, is a U.S. senator from Arkansas.