New START Treaty Expires, Ending US-Russia Nuclear Limits

The New START treaty between the United States and Russia expired on February 5, 2026, ending the last remaining agreement that set limits on their deployed strategic nuclear warheads. This marks the first time since the early 1970s with no legal bounds on the nuclear forces of the world's two largest nuclear powers. The treaty's end comes after years of strained relations, including Russia's invasion of Ukraine and mutual suspensions of inspections and data sharing.

Background

New START, signed in 2010 by US President Barack Obama and Russian President Dmitry Medvedev, took effect in 2011. It set clear caps: each side could deploy no more than 1,550 strategic nuclear warheads, 800 deployed and non-deployed launchers, and 700 deployed intercontinental ballistic missiles, submarine-launched ballistic missiles, or heavy bombers. These were systems designed to strike across continents, from Europe to the US or vice versa.

The deal built on earlier pacts from the Cold War era, like SALT I in 1969, which started formal talks to curb the arms race. Over decades, these agreements cut huge stockpiles built up during tense times. New START allowed one five-year extension, agreed in 2021, pushing its end date to today. No further extension was possible under its rules.

Tensions grew after Russia invaded Ukraine in 2022. In February 2023, the US said Russia was not following the treaty. Weeks later, Russian President Vladimir Putin announced Russia would suspend its participation. This stopped on-site inspections, where experts from one country could visit the other's bases, and ended required data exchanges on warhead numbers and launcher movements. The US then halted some of its own information sharing. Even so, both sides said they kept to the numerical caps.

Key Details

New START's core was verification. Teams conducted over 400 inspections in the first decade, giving each side confidence the other was not cheating. Notifications about test launches or movements added transparency. Without these, trust eroded, but the limits still shaped plans.

Russia proposed in September 2025 to stick to the caps for another year after expiration. US President Donald Trump called it a good idea at first. Later, he said if it expires, it expires, and talked of a better deal that would include China. No formal talks followed. Moscow said it lacked clear contacts in the US government. China, with about 600 warheads compared to over 5,000 each for the US and Russia, has said it won't join talks until its arsenal grows.

The treaty's end fits a pattern. Most US-Russia arms pacts have ended or been dropped. This leaves no bilateral deal on strategic weapons. Both countries maintain large reserves: thousands of warheads in storage that could be added to missiles if needed.

Recent Moves and Statements

Russia's Foreign Ministry issued a statement noting the expiration. US officials have not announced immediate changes to forces. Trump has pushed for new negotiations, but details remain unclear. Analysts note the timing: the Nuclear Non-Proliferation Treaty review starts in late April in New York. There, nuclear states must report on disarmament progress.

"If it expires, it expires." – US President Donald Trump

What This Means

Without limits, each side may plan for worst-case scenarios. Russia might add warheads to existing missiles, a process called uploading. The US could expand submarine fleets or bomber wings. This uncertainty could spark faster buildup, like during the Cold War.

Crises become riskier without data sharing. In a standoff, leaders lack clear views of the other's forces, raising accident chances. Strategic stability, the balance that discourages first strikes, weakens.

Other nations watch closely. The non-proliferation treaty requires nuclear powers to pursue disarmament. Its end without a replacement could strain that pact, pushing non-nuclear states to question commitments. Some might seek their own weapons.

Short-term, no big changes are expected right away. Both arsenals stay near old caps. But over months, budgets may shift to new systems. The US is modernizing its entire nuclear triad: land missiles, subs, and bombers. Russia does the same.

Talks for a follow-on deal face hurdles. Including China appeals but complicates things. Beijing wants parity first. Multilateral talks need time, which is short amid Ukraine war and other conflicts.

The world now has no enforceable caps on the biggest nuclear threats. This shift ends over 50 years of managed competition. Leaders in Washington and Moscow must decide next steps amid high stakes.