SALT, in international diplomacy, the common name for negotiations and treaties between the United States and the Soviet Union intended to limit strategic nuclear weapon strength of each nation. (SALT refers to both “Strategic Arms Limitations Talks” and “Strategic Arms Limitations Treaty.”) Strategic weapons include (1) land-and submarine-based offensive ballistic missiles, (2) land-based anti-ballistic interceptor missiles (ABM's), (3) long-range bombers armed with nuclear bombs, and (4) cruise missiles (small, unmanned airplanes with nuclear warheads) launched from bombers or submarines.

The first series of negotiations, SALT I, resulted in a treaty and an interim agreement in 1972. The treaty provided that each country could deploy up to 200 ABM's, but limited to two sites with no more than 100 missiles on each. In 1974 the two nations agreed to limit ABM's to just one site. The United States dismantled its ABM's in 1976; the Soviet Union chose Moscow as its single site. (Russia, after the Soviet Union broke up in 1991, continued to deploy the ABM's there.) The interim agreement limited for five years the number of each nation's offensive ballistic missiles.

Negotiations for SALT II were held during 1972–79, and a treaty was signed placing limitations on all kinds of strategic weapons and weapon systems. Opponents of SALT II in the United States contended that the nature of the limitations left the Soviets with an advantage and blocked ratification in the U.S. Senate. Nevertheless, at first both the United States and the Soviet Union adhered to the arms-limitations provisions of SALT II. In 1987, however, President Reagan authorized the building of more launch vehicles than allowed by the treaty.