Columna CISAC (Stanford) Commentary, 02.10.2025 Steven K. Pifer, embajador ® y académico norteamericano (Stanford-Brookings)
With the [New START] treaty due to expire in February 2026, the Trump administration must decide how to respond to a Russian proposal to extend the treaty’s quantitative limits for one year.
The 2010 New Strategic Arms Reduction Treaty (New START) reduced U.S. and Russian strategic offensive nuclear arms numbers to levels not seen since the 1960s. With the treaty due to expire in February 2026, the Trump administration must decide how to respond to a Russian proposal to extend the treaty’s quantitative limits for one year. Such an extension could well be in the U.S. interest, but President Trump needs to consider the question with open eyes.
New START
New START’s numerical limits took full effect in 2018. Those limits constrain each side to:
- No more than 700 deployed intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs) and nuclear-capable bombers;
- No more than 800 deployed and non-deployed ICBM and SLBM launchers and nuclear-capable bombers; and
- No more than 1550 deployed strategic warheads.
The treaty’s verification provisions provide for data exchanges, notifications and on-site inspections to verify compliance with the numerical limits. Implementation of those provisions has been in dispute in recent years. In 2020, Washington and Moscow mutually agreed to suspend on-site inspections due to COVID-19. However, in 2022, the United States proposed resumption of inspections, but the Russians refused. In February 2023, angered at U.S. support for Ukraine, Russian President Putin said Russia would suspend its observance of the treaty.
Officials in Moscow clarified that Russia would continue to observe New START’s three numerical limits until the treaty’s expiration in 2026. In June 2023, Washington suspended its implementation of New START’s verification provisions, saying it also would continue to abide by the numerical limits.
Absent the treaty’s verification measures, the United States and Russia likely can monitor the other’s compliance with the 700 and 800 limits using national technical means of verification, such as imagery satellites, with fairly high confidence. However, monitoring the 1550 limit without notifications and on-site inspections poses a more difficult challenge. In a January 2025 report, the U.S. government assessed that Russia may have exceeded the 1550 limit during 2024.
At their August 2025 meeting in Alaska, the Trump-Putin discussion reportedly touched on strategic stability and New START’s looming expiration. However, the discussion between the presidents did not get into details.
Putin’s Extension Offer
On September 22, 2025, Putin said that “Russia is prepared to continue adhering to the central quantitative limitations of the New START treaty for one year after February 5, 2026,” provided that the United States did the same. On October 2, the Kremlin spokesman commented that “there has been no [U.S.] response yet” to Putin’s proposal.
The lack of response seems a bit odd. In July, Trump commented that New START was “not an agreement you want expiring.” In August, he expressed interest in “denuclearization”—a concept he did not further define—and suggested that Russia and China were also interested.
How Should Washington Proceed?
The Trump administration should weigh Putin’s proposal with care. Extension could have downsides. First, the Russian leader did not indicate readiness to resume or extend New START’s verification measures. Absent those measures, U.S. confidence in Russian adherence to the 1550 deployed strategic warhead limit will degrade over time.
Second, Russia’s record on compliance with nuclear arms control agreements offers few grounds for confidence. Moscow’s refusal to host on-site inspections in 2022 violated New START’s requirements, and the treaty makes no provision for the “suspension” of verification provisions that Putin announced in 2023. Moreover, Russia’s violation of the 1987 Intermediate-range Nuclear Forces Treaty by developing and testing a prohibited ground-launched cruise missile led to that treaty’s demise in 2019.
Third, China’s dramatic expansion of its nuclear forces concerns Defense Department planners as much, if not more than, Russian nuclear activities. That has prompted thinking in defense and military circles about a need to increase deployed U.S. strategic warheads by “uploading” existing delivery systems, that is, placing more warheads on ICBMs, SLBMs and nuclear-capable bombers that now do not carry or are not slated to carry their maximum loadings. China has made clear, most recently in August, that it will not take part in nuclear arms talks with the United States and Russia.
All that said, the United States hardly finds itself defenseless. It maintains some 3700 total nuclear warheads in its active inventory (non-deployed strategic warheads and non-strategic warheads in addition to the deployed strategic warheads constrained by New START). That compares to about 4300 for Russia. China has about 600, while the British and French together total some 500.
Agreeing to Putin’s offer would maintain a useful measure of predictability in the tense U.S.-Russia relationship and could slow, if only for one year, a three-way nuclear arms race with Russia and China that has begun gathering steam. Moreover, it would buy time to explore whether future constraints on nuclear arms—whether a modified New START treaty or some other agreement—are possible with Russia. Trump could link his readiness to agree to New START’s extension to Russian agreement to bilateral discussions on strategic stability and possible future constraints on U.S. and Russian nuclear forces.
Such discussions would invariably have to deal with difficult questions. While the United States would like to limit Chinese nuclear forces, the Russians would raise British and French nuclear arms. The Trump administration in its first term sought to constrain all nuclear weapons, not just deployed strategic warheads, a proposal the Russians refused to take up. Moscow has long sought to limit missile defenses, an issue on which Washington is reluctant to engage. The dialogue itself could prove useful after a more than three-year gap, though the discussions might or might not produce areas of agreement.
On balance, a one-year treaty extension seems worth a try. The expiration of New START would mean the end of the only remaining constraint on U.S. and Russian nuclear force levels. If the United States then proceeds to increase the number of its deployed strategic warhead above the New START level, Russia will almost certainly increase its strategic arms numbers, and China may consider increasing its already expansive plans.
The risks of extension appear manageable. Even with current trends, the nuclear balance would not deteriorate much by early 2027. The United States would retain the option of uploading its strategic systems.
Absent an extension, the United States and Russia will find themselves along with China in an unconstrained arms race. The question then would be how long it might take for the three to recall the lesson that Washington and Moscow learned in the 1960s: if your side adds more nuclear weapons to its arsenal and the other side (or sides) does the same, your side likely will not achieve a net increase in its security. Instead, it will see increased instability, greater nuclear risk and higher nuclear force costs.
Could Washington and Moscow relearn that lesson by 2027? Perhaps, perhaps not, but one year of restraint would not risk much against a possible pay-off that could mean greater security for the United States and the world.
