Strategic Arms Limitation Treaty I
The negotiations known as Strategic Arms Limitation Talks began in November 1969 and ended in January 1972, with agreement on two documents: the Anti-Ballistic Missile Treaty (ABM Treaty) and the Interim Agreement on the Limitation of Strategic Offensive Arms. Both were signed on May 26, 1972.
Interim Agreement between the U.S. and U.S.S.R. of five-year duration which froze the number of strategic ballistic missiles at 1972 levels. Construction of additional land-based ICBM silos were prohibited, while SLBM launcher levels can be increased if corresponding reductions are made in older ICBM or SLBM launchers. Modernization of launchers is allowed, however, if kept within specific dimensions.
SALT I, the first series of Strategic Arms Limitation Talks, extended from November 1969 to May 1972. During that period the United States and the Soviet Union negotiated the first agreements to place limits and restraints on some of their central and most important armaments. In a Treaty on the Limitation of Anti-Ballistic Missile Systems, they moved to end an emerging competition in defensive systems that threatened to spur offensive competition to still greater heights. In an Interim Agreement on Certain Measures With Respect to the Limitation of Strategic Offensive Arms, the two nations took the first steps to check the rivalry in their most powerful land- and submarine-based offensive nuclear weapons.
Soviet and American weapons systems were far from symmetrical. The Soviet Union had continued its development and deployment of heavy ballistic missiles and had overtaken the U.S. lead in land-based ICBMs. During the SALT I years alone Soviet ICBMs rose from around 1,000 to around 1,500, and they were being deployed at the rate of some 200 annually. Soviet submarine-based launchers had quadrupled. The huge payload capacity of some Soviet missiles ("throw-weight") was seen as a possible threat to U.S. land-based strategic missiles even in heavily protected ("hardened") launch-sites.
The United States had not increased its deployment of strategic missiles since 1967 (when its ICBMs numbered 1,054 and its SLBMs 656), but it was conducting a vigorous program of equipping missiles with "Multiple Independently-targeted Re-entry Vehicles" (MIRV). "MIRVs" permit an individual missile to carry a number of warheads directed at separate targets. MIRVs thus gave the United States a lead in numbers of warheads. The United States also retained a lead in long-range bombers. The Soviet Union had a limited ABM system around Moscow; the United States had shifted from its earlier plan for a "thin" ABM defense of certain American cities and instead began to deploy ABMs at two land-based ICBM missile sites to protect its retaliatory forces. (The full program envisaged 12 ABM complexes.)
Besides these asymmetries in their strategic forces, the defense needs and commitments of the two parties differed materially. The United States had obligations for the defense of allies overseas, such as Western Europe and Japan, while the Soviet Unions allies were its near neighbors. All these circumstances made for difficulties in equating specific weapons, or categories of weapons, and in defining overall strategic equivalence.
In a summit meeting in Moscow, after two and a half years of negotiation, the first round of SALT was brought to a conclusion on May 26, 1972, when President Nixon and General Secretary Brezhnev signed the ABM Treaty and the Interim Agreement on strategic offensive arms.
Intensive research had gone into finding ways of verifying possible agreements without requiring access to the territory of the other side. Both the ABM Treaty and the Interim Agreement stipulate that compliance is to be assured by "national technical means of verification." Moreover, the agreements include provisions that are important steps to strengthen assurance against violations: both sides undertake not to interfere with national technical means of verification. In addition, both countries agree not to use deliberate concealment measures to impede verification.
Source: Department of State