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.
The chairmen of the House foreign affairs and intelligence committees are pushing a measure meant to extend the last remaining U.S.-Russia arms control agreement amid fears President Donald Trump will let it lapse.