The Anti-Ballistic Missile Treaty (ABM) (1972-2002) was an arms control treaty between the United States and the Soviet Union on the limitation of ballistic missile defence systems (ABM). According to the treaty, each side was limited to two ABM complexes, each limited to 100 anti-ballistic missiles.  The link between strategic arms restrictions and outstanding issues such as the Middle East, Berlin and especially Vietnam has become the central focus of Nixon and Kissinger`s détente policy. By making connections, they hoped to change the nature and direction of American foreign policy, including the U.S. policy of nuclear disarmament and arms control, and separate it from those practiced by Nixon`s predecessors. They also intended to make U.S. gun control policy part of the pull-up by The Link. […] Its link policy had indeed failed. It failed mainly because it was based on erroneous assumptions and erroneous premises, which the Soviet Union wanted above all a strategic arms control agreement, far more than the United States.
 The most important element of the summit was the salt agreements. Discussions on SALT have been going on for about two and a half years, but with little progress. However, during the meeting between Nixon and Brezhnev in May 1972, a monumental breakthrough was made. The SALT de accords signed on 27 May dealt with two important issues. First, they limited the number of anti-ballistic missile (ABM) sites to two. (ABMs were missiles designed to destroy arriving missiles.) Second, the number of intercontinental missiles and submarine-launched ballistic missiles has been frozen at current levels. However, the agreements have done nothing on several independent return missiles (individual missiles with several nuclear warheads) or on the development of new weapons. Yet most Americans and Soviets hailed the salts agreements as huge achievements. Nixon and Brezhnev seemed to be unlikely candidates for American and Soviet statesmen to sign a revolutionary arms limitation treaty. Both men had a reputation as hardened Cold War warriors.
Nevertheless, until 1972, the two heads of state and government sought to establish closer diplomatic relations between their respective nations. The Soviet Union was involved in an increasingly hostile war of words with Communist China; Border conflicts between the two nations had erupted in recent years. The United States sought help to free itself from the unpopular and costly war in Vietnam. Nixon, in particular, wanted to divert American public opinion from the fact that he had failed to end the conflict for nearly four years as president. The summit between Nixon and Brezhnev in May 1972 was a good time to follow the closer relations desired. SALT I is the common name of the agreement on strategic arms control talks 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.