https://www.icanw.org/new_start_expiration
What did New START do?
New START, which was initially agreed in 2010 and extended for five years in 2021, limited U.S. and Russian deployed, strategic nuclear weapon arsenals. There is no agreed definition of what constitutes a “strategic” or “non-strategic” nuclear weapon, but the treaty defines strategic nuclear weapons systems as those that are “intercontinental in range” i.e. that can be launched from Europe and detonated in the United States and vice-versa.
The Treaty limited the United States and Russia to 1,550 deployed strategic nuclear warheads on 700 deployed nuclear delivery systems (airplanes, intercontinental ballistic missiles and submarine-launched missiles) and to 800 deployed and non-deployed nuclear launchers of those missiles and airplanes that can launch nuclear weapons.
Since the treaty only applies to strategic and deployed nuclear weapons, both countries have larger nuclear arsenals, with Russia estimated to possess 5,459 nuclear warheads and the United States 5,177.
It also required regular short-notice, on-site inspections and biannual data exchange between the two countries.
ICAN's Executive Director on the expiration of new START
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Why did it expire?
Under the terms of the treaty, New START could only be extended once, so it was always going to end on 5 February 2026. But Russia and the United States could have agreed to a new deal to take effect when New START lapsed. Russia suggested in September 2025 that the United States and Russia agree to abide by the limits in New START for an additional year, to which U.S. President Trump originally re-acted positively. But Trump also has repeatedly expressed interest, as recently as January, in negotiating a new agreement, including China, and seemed unconcerned about the lapse of New START.
New START has been under stress for many years. While both Russia and the United States have, according to open-source estimates, maintained the limits required by New START thus far, the treaty’s verification provisions have not been fully implemented for some time. In 2020, due to the COVID pandemic, both sides halted on-site inspections. Following the increase in tension between the two countries over the Russian invasion of Ukraine and US military support for Kiev, the United States assessed that Russia was in non-compliance with the treaty in February 2023, and several weeks later, Russian President Putin declared that Russia would suspend its compliance with the treaty, rejecting inspections and data exchange with the United States. The United States responded by deciding to no longer share some information with Russia required by New START.
What does this mean?
While Russian and U.S. nuclear arsenals under New START limits already posed an unacceptable threat to humanity, without it, the risk of nuclear use will likely increase, due to the possibility of a heightened nuclear arms race. It is in no country’s interest to increase global nuclear arsenals. Instead, all nuclear-armed states should adhere to and implement existing international agreements on nuclear disarmament.
While New START may have expired, the legal obligation of Russia, the United States, and other nuclear-weapon states to negotiate nuclear disarmament and an end to the arms race has not. This obligation comes from the Nuclear Nonproliferation Treaty, adopted in 1968 and indefinitely extended in 1995. The next Review Conference of this Treaty will take place this April-May in New York, and is when nuclear-weapon states must explain what progress they have made on their implementation of the Treaty in the past five years, and how they intend to take forward this commitment in the coming five years. At times of high tension among nations, disarmament measures are all the more important. The dire international security environment at present, rather than serving as an excuse for inaction, must spur urgent action on disarmament.
The Treaty on the Prohibition of Nuclear (TPNW) plays a key role in these uncertain times. It is the only globally applicable treaty in force that explicitly bans nuclear weapons activities, from nuclear use to nuclear testing to nuclear development. It sends a strong message that a renewed arms race is not only morally unacceptable but illegal under international law in most of the world. At time of writing a majority of countries are either states parties or signatories of the TPNW. Every country that joins this Treaty sends a strong message to nuclear-armed states that they are on the wrong side of history. Joining the TPNW is an important step that all countries can take to press for disarmament in these dangerous times.
