New START expires
The last treaty limiting American and Russian nuclear arsenals lapses.
- When
- Known to
- ± 12 hours
- Era
- Contemporary, Holocene
The treaty expired on 5 February 2026 with no successor, leaving the two states holding roughly 90% of the world's nuclear weapons without any negotiated ceiling or inspection regime for the first time since 1972. Inspections had already been suspended since 2023. China, meanwhile, has been expanding its own arsenal outside any treaty framework.