The Uncertain Future of the New START Treaty

With the New START Treaty supended by the Russian Federation the future of legal nuclear arms control looks even bleaker than before. This brief lays out the foundations of the treaty and the main obstacles that it faces even before it expires in 2026.

Executive Summary 

This Deep Cuts Commission issue brief describes the background and implementation of the New Strategic Arms Reduction Treaty (New START), the impact of Russia’s suspension of the treaty and the treaty’s uncertain future. 

New START is a bilateral treaty between the United States and Russia, signed in 2010. When its numerical limits took full effect in 2018, U.S. and Russian strategic offensive forces had reduced to their lowest levels in five decades. The two countries implemented the treaty through 2022, despite their difficult bilateral relations, indicating that they considered constraining their competition in strategic nuclear arms a mutual interest. 

In February 2023, President Vladimir Putin announced that Russia would “suspend” its participation in New START, citing U.S. support for Ukraine in its war with Russia. Russian officials subsequently explained that Moscow would continue to observe the treaty’s numerical limits but would not implement its monitoring and verification provisions. Still, Putin’s decision was a departure from the general practice observed by the United States and Soviet Union/Russia of “compartmentalizing” arms control, that is, continuing to pursue and implement agreements even when the broader relationship hit difficult stretches. Washington responded with countermeasures, including halting its implementation of verification provisions. 

The sides likely can monitor with fairly high confidence the number of the other’s strategic ballistic missiles, strategic ballistic missile launchers, and heavy bombers using their national technical means of verification. However, they will have less confidence over time that the other is observing New START’s limit on deployed strategic warheads absent the notifications and on-site inspections provided for by the treaty. 

Ideally, the sides would return to full implementation of New START. This would restore confidence that the sides were observing all three of the treaty’s numerical limits. It would also allow Russia to pursue its issues with U.S. conversion practices and the United States to raise questions about new kinds of Russian strategic arms. Having the treaty in full force would provide a more solid foundation for discussions on what might follow New START, when it expires by its terms in February 2026. 

In June 2023, Washington proposed a dialogue on managing nuclear risks and the post-2026 arms control framework without preconditions. As of late November, there is no sign that Moscow is prepared to agree to that so long as U.S. support for Ukraine continues. Nothing suggests that the Biden administration is prepared to curtail that support. 

Absent the treaty’s monitoring and verification measures, concern could arise that one side or the other is exceeding the numerical limit on deployed strategic warheads, for example, by adding extra warheads on strategic ballistic missiles that currently carry fewer than their maximum capacity. That could prompt a side to exercise its right to withdraw from the treaty. 

However, the most likely scenario appears to be continued Russian suspension until the treaty’s expiration in February 2026 and, during that period, no serious arms control dialogue between Washington and Moscow. That would occur against the backdrop of growing U.S. concern about the ongoing expansion of Chinese nuclear forces, which has already led some to suggest that the United States will need to increase its strategic forces beyond the limits of New START. 

The United States, Russia, and China face the prospect of a three-way nuclear arms race. Avoiding that will require creative diplomacy and recalling, or relearning, the lessons of the 1960s. Washington and Moscow then concluded that adding larger numbers of nuclear weapons beyond a certain point did not enhance their security and that arms control made sense.

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