The treaty was intended to build trust between Russia and the West by allowing the accord’s more than three dozen signatories to conduct reconnaissance flights over each other’s territories.
With the official withdrawal from the treaty, which allowed the U.S. and Russia overflight rights to inspect military facilities, only one arms-control pact is still in force between the former Cold War foes.
New START, which limits each country to no more than 1,550 deployed nuclear warheads and 700 deployed missiles and bombers, expires Feb. 5 unless the U.S. and Russia agree to extend it.