Nuclear Non-Deterrence: war in Ukraine makes non-conclusion of a new treaty on strategic offensive arms limitation more plausible

The Treaty between the United States and Russia on Measures for the Further Reduction and Limitation of Strategic Offensive Arms (New START) expires in February 2026. Even before, the new treaty did not look like an easy task because of the parties' serious disagreement over the status of the Russian "Kindzhal", "Burevestnik " and "Poseidon" missiles, but after the outbreak of war, the very possibility of this treaty has been called into question. As a result, it looks quite possible that in 2026, for the first time since 1972, the two largest nuclear arsenals will be left without mutual control, which is likely to lead to a new nuclear arms race, according to experts monitoring The Nuclear Notebook.

At the time of its signing in 2010, the New START was a significant achievement of international diplomacy in the field of nuclear disarmament: it has not only limited the nuclear arsenals of the United States and Russia to 1,550 nuclear charges and 700 carriers each (the 1991 Russian-American START I allowed one party to have up to 6,000 nuclear charges) but also included a complex system of information verification on the parties' nuclear arsenals. The agreement expires in a few years, but the preparation of a new treaty will take time, so it must begin now, according to the experts on nuclear disarmament, who have been publishing The Nuclear Notebook on The Bulletin of the Atomic Scientists platform since 1987.

Although the Biden administration had time to take steps toward discussing a new nuclear disarmament agreement, negotiations were suspended by the United States after the Russian invasion of Ukraine.

"Without the new treaty, the Russian and American military and politicians will have to rely on each other's worst-case scenarios of behavior, which, in turn, will lead to an unreasonably costly arms race and a hard-to-predict escalation," some experts believe.

After the New START expires countries will be able to double their arsenals simply by increasing a load of carriers to the maximum possible. In such a scenario, the United States would be able to use more warheads than Russia, but Russia would have a larger nuclear arsenal due to its significant stock of non-strategic weapons. Experts point out that a quantitative increase in the number of warheads on both sides is also possible, especially if the threat from China will be growing, but for both Russia and the United States this would entail too much burden on the state budget, and therefore such a development is considered very unlikely.

Nuclear arsenals of Russia and the United States: warheads

Russian and U.S. nuclear arsenals: carriers

Existing outside nuclear disarmament treaties benefit no one, the Bulletin of the Atomic Scientists experts believe. In this situation, both countries will be forced to strengthen their intelligence capabilities to compensate for uncertainties regarding the other's nuclear forces. Both will invest more in what they believe will increase each other's overall military capabilities — missiles, non-strategic nuclear arsenals, and air defense, in other words, will get mired in additional military expenses. In addition, the United States and Russia's nuclear build-up may provoke reactions from other nuclear-weapon states, who may also decide to increase their nuclear forces and reconsider their role in their military strategies.

It is possible to maintain bilateral American and Russian control over nuclear weapons by extending previous agreements, adopting a new agreement without its mandatory ratification, or formally concluding a new treaty. The advantage of the first two options is that they do not require legislative approval and therefore will take less time to implement. However, in such a case the implementation of the agreements depends entirely on the political will of the parties: the ordinary legislation of both countries does not allow foreign nationals to be present at military facilities, which means that verification procedures will not be possible.

If the countries choose the option of voluntarily complying with the agreements not backed by new treaty ratification, the current bilateral consultative commission will also cease to exist, and if one side accuses the other of violating the agreement, there will be no ready mechanism for resolving the dispute.

The conclusion of a new formal agreement will require both countries to compromise. Experts speak of three main U.S. national security objectives regarding Russian-American "nuclear" relations: maintaining mutual restrictions after 2026, establishing control over new types of Russian weapons, and limiting all Russian nuclear weapons. While Russia will quite likely support the first objective, the second is already causing Russian-American disagreements. The United States considers Russia's "Burevestnik," "Kinzhal," and "Poseidon" missiles, introduced by Putin in his 2018 address to the Federal Assembly, to be new types of nuclear weapons, but Russia disagrees and does not believe they should be included in a future agreement.

As for limiting all of Russia's nuclear weapons, "this task is the biggest challenge, given the complexity of the verification procedure for the existing arsenal and the imbalance of nuclear forces. Including non-strategic nuclear weapons in an arms control treaty would require years of negotiations and the establishment of a new, trusting American-Russian relationship," The Nuclear Notebook authors wrote.

However, despite the ongoing escalation of the conflict in Ukraine, there is still hope for a new treaty: even though Russian authorities refused to allow the United States to inspect its nuclear facilities in August, in late October the State Department announced that both sides were ready to resume negotiations.