New START lapses, ending 50 years of US–Russia arms control
The last treaty capping the two largest arsenals expired 5 February 2026 with no successor and no inspections
Summary
New Start — the last treaty capping the US and Russian strategic arsenals — expired on 5 February 2026 with no successor, ending roughly half a century of bilateral arms control. The treaty had limited each side to 1,550 deployed warheads on 700 delivery vehicles and mandated on-site inspections and biannual data exchange; Moscow suspended compliance in 2023 after the Ukraine invasion, so verification had already collapsed. On 4 February Russia's foreign ministry said it no longer considered the obligations binding. The Trump administration says any successor must include China — a demand Beijing rejects. The loss of inspections, more than the numerical cap, is what analysts (CFR, Brookings) flag as the durable damage to mutual transparency.
By the numbers
- 5 Feb 2026 — date the treaty lapsed.
- 1,550 — deployed strategic warheads each side was capped at.
- 700 — deployed delivery vehicles (ICBMs, SLBMs, bombers) each side was capped at.
- 2023 — year Russia suspended compliance, ending inspections.
- ~90% — share of the world's warheads held by the two parties.
Why it matters
No legal ceiling now binds the two largest arsenals, and no inspection regime verifies either side's deployments. The hedge each builds against the other becomes harder to read, raising miscalculation risk and feeding Proliferation pressure on fence-sitters who relied on great-power restraint.
What to watch
- Whether Washington and Moscow keep informally observing the central limits.
- Any US move to upload warheads in response to Russia or China.
- Whether Trump's China-inclusion demand kills all successor talks.