New START Treaty Expires: First Time Since 1970s With No Nuclear Arms Control

What Happened

On February 5, 2026, the New Strategic Arms Reduction Treaty (New START) formally expired, ending the last legally binding nuclear arms control agreement between the United States and Russia. No successor treaty has been negotiated or is currently under negotiation. For the first time since the early 1970s — over five decades — there are no binding limits on the strategic nuclear forces of the two nations that together possess approximately 90% of the world's nuclear weapons.

What Was Lost

New START, originally signed in 2010 and extended for five years in 2021, imposed the following limits on each side:

• 1,550 deployed strategic nuclear warheads
• 700 deployed intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and heavy bombers
• 800 deployed and non-deployed ICBM launchers, SLBM launchers, and heavy bombers

Beyond the numerical limits, the treaty established a comprehensive verification regime that included on-site inspections, regular data exchanges on force composition and deployments, notifications of changes, and a Bilateral Consultative Commission (BCC) for resolving compliance questions. These transparency mechanisms provided both sides with insights into the other's nuclear posture, reducing the risk of miscalculation and worst-case planning.

The Path to Expiration

Russia suspended compliance with New START in February 2023 following the escalation of tensions over Ukraine, halting inspections and data exchanges. In September 2025, Russian President Putin publicly proposed that both nations continue to observe New START limits for one year after the treaty's expiration. The United States did not formally respond to this proposal. Instead, President Trump posted on social media on February 5, 2026, that the US would seek a "new, improved, and modernized Treaty that can last long into the future" — without initiating negotiations.

Legal Analysis

The expiration of New START implicates the nuclear disarmament obligations that both the United States and Russia have undertaken under international law:

NPT Article VI: Both the US and Russia are parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), which requires them "to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament." Allowing the last arms control treaty to lapse without pursuing a successor raises questions about compliance with this obligation.

ICJ Advisory Opinion (1996): The International Court of Justice unanimously concluded that "there exists an obligation to pursue in good faith and bring to a conclusion negotiations leading to nuclear disarmament in all its aspects under strict and effective international control." Letting New START expire without engaged negotiations to replace it is arguably inconsistent with this obligation.

Enabling classification: While the treaty's expiration does not itself constitute a war crime, it removes the structural constraints that prevent nuclear escalation. It enables worst-case planning, unconstrained arms buildups, and increases the risk of nuclear conflict — making it an enabling condition for potential future catastrophic harm.

Why This Is Classified Critical

This incident receives a critical severity classification because:

• Historic rupture: The first time in over 50 years that the world's two largest nuclear arsenals face no legally binding constraints. This is not merely a policy setback — it is the collapse of an entire framework of nuclear restraint.
• Scale of risk: Approximately 12,000 nuclear warheads between the US and Russia are now unconstrained. The potential consequences of miscalculation or escalation are existential.
• Loss of verification: The end of inspections, data exchanges, and the BCC removes critical transparency mechanisms that have prevented miscalculation for decades.
• No negotiations underway: Neither side is engaged in negotiations for a successor treaty. The US called for a new treaty without initiating talks. Russia's proposal to maintain limits was ignored.
• Compounding factors: Combined with Trump's October 2025 order to resume nuclear testing, the treaty's expiration creates a dual erosion of nuclear norms.

International Law Violations

The following international law provisions are implicated:

1. NPT Article VI (Obligation to Negotiate Disarmament): Allowing the last arms control treaty to expire without pursuing a successor raises serious questions about good-faith compliance with NPT obligations.
2. ICJ Advisory Opinion (Nuclear Disarmament Obligation): The unanimous ICJ conclusion that states must pursue and conclude nuclear disarmament negotiations creates a legal obligation that the treaty's lapse arguably violates.
3. UN Charter Article 26 (Armaments Regulation): The Security Council's mandate to establish systems for regulating armaments is undermined when the foundational bilateral framework collapses.
4. Treaty on the Prohibition of Nuclear Weapons: While neither the US nor Russia has signed the TPNW, it reflects the growing international consensus that nuclear weapons are inherently contrary to international humanitarian law — a consensus that the treaty's expiration moves further away from.