SALT I Treaty
SALT I is the common name for the Strategic Arms Limitation Talks Agreement signed on May 26, 1972. SALT I froze the number of strategic ballistic missile launchers at existing levels and provided for the addition of new submarine-launched ballistic missile (SLBM) launchers only after the same number of older intercontinental ballistic missile (ICBM) and SLBM launchers had been dismantled. SALT I also limited land-based ICBMs that were in range from the northeastern border of the continental United States to the northwestern border of the continental USSR. In addition to that, SALT I limited the number of SLBM capable submarines that NATO and the United States could operate to 50 with a maximum of 800 SLBM launchers between them. If the United States or NATO were to increase that number, the USSR could respond with increasing their arsenal by the same amount.
The strategic nuclear forces of the Soviet Union and the United States were changing in character in 1968. The total number of missiles held by the United States had been static since 1967 at 1,054 ICBMs and 656 SLBMs but there was an increasing number of missiles with multiple independently targetable reentry vehicle (MIRV) warheads being deployed. MIRVs carried multiple nuclear warheads, often with dummies, to confuse ABM systems, making MIRV defense by ABM systems increasingly difficult and expensive. Both sides were also permitted to increase their number of SLBM forces, but only after disassembling an equivalent number of older ICBMs or SLBM launchers on older submarines.
One clause of the treaty required both countries to limit the number of deployment sites protected by an anti-ballistic missile (ABM) system to one each. The idea of this system was that it would prevent a competition in ABM deployment between the US and the Soviet Union. The Soviet Union had deployed such a system around Moscow in 1966 and the United States announced an ABM program to protect twelve ICBM sites in 1967. After 1968, the Soviet Union tested a system for the SS-9 missile, otherwise known as the R-36 missile. A modified two-tier Moscow ABM system is still used. The United States built only one ABM site to protect a Minuteman base in North Dakota where the "Safeguard" Program was deployed. This base was increasingly more vulnerable to attacks by the Soviet ICBMs, because of the advancement in Soviet missile technology.
Negotiations lasted from November 17, 1969, until May 1972 in a series of meetings beginning in Helsinki, with the US delegation headed by Gerard C. Smith, director of the Arms Control and Disarmament Agency. Subsequent sessions alternated between Vienna and Helsinki. After a long deadlock, the first results of SALT I came in May 1971, when an agreement was reached over ABM systems. Further discussion brought the negotiations to an end on May 26, 1972, in Moscow when Richard Nixon and Leonid Brezhnev signed both the Anti-Ballistic Missile Treaty and the Interim Agreement Between The United States of America and The Union of Soviet Socialist Republics on Certain Measures With Respect to the Limitation of Strategic Offensive Arms. A number of agreed statements were also made. This helped improve relations between the United States and the USSR.