1. Each contracting party undertakes not to start building additional fixed launchers of the ICBM. A clause in the treaty required both countries to limit the number of areas of intervention protected by an anti-ballistic missile (ABM) system to one. The idea of this system was that it would prevent competition in the application of the ABM between the United States and the Soviet Union. The Soviet Union had set up such a system around Moscow in 1966 and the United States announced in 1967 a protection program of 12 ICBM sites. After 1968, the Soviet Union tested an SS-9 missile system, also known as the R-36 missile.  A two-tiered Moscow ABM system continues to be used. The United States has built only one ABM site to protect a minuteman base in North Dakota, where the “Safeguard” program was implemented. This base was increasingly vulnerable to attacks by Soviet ICBMs due to advances in Soviet missile technology. Negotiations continued from November 17, 1969 to May 1972, in a series of meetings that began in Helsinki, with the U.S. delegation led by Gerard C. Smith, Director of the Arms Control and Disarmament Agency. The following meetings took place between Vienna and Helsinki.
After a long deadlock, the first results of SALT I arrived in May 1971, when an agreement was reached on the ABM systems. Further talks ended negotiations on 26 May 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 to limit strategic offensive weapons.  SALT I is the usual name of 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 proposed the addition of new submarine missile launchers (LBMs) only after the same number of older intercontinental missiles (ICBMs) and SLBM launchers were dismantled.  SALT I also limited land-based ICBMs from the northeastern border of the continental United States to the northwest border of the continental USSR.  In addition, SALT I has limited to 50 the number of SLBM-compatible submarines that can be operated by NATO and the United States, with a maximum of 800 SLBM launchers between them. If the United States or NATO increased this figure, the USSR could respond by increasing its arsenal by the same amount. The SALT II negotiations were opened at the end of 1972 and lasted seven years.
A fundamental problem in these negotiations was the asymmetry between the strategic forces of the two countries, as the USSR had concentrated on missiles equipped with large warheads, while the United States had developed smaller missiles with greater precision. Questions were also raised about new technologies in development, definition questions and verification methods. The contracting parties agreed not to begin the construction of additional intercontinental missile launchers (ICBMs) after 1 July 1972 (Article I); The agreed Declaration A specified that fixed ground launchers under construction could be completed at the time of the signing of the agreement. The agreement required contracting parties not to convert older ground launchers or light launchers into ground launchers for heavy ICT types used after 1964 (Article II). The agreement also limited the number of ballistic missiles (SLBM) launched by modern submarines and ballistic missiles, among others, to submarines operational and under construction at the time of the signing of the agreement (Article III). In early 1975, delegations in Geneva resumed negotiations and worked on an agreement based on this general framework.