The salt-II debate in the U.S. Congress lasted for months. However, in December 1979, the Soviets launched an invasion of Afghanistan. The Soviet attack killed virtually every chance of going through SALT-II, and Carter made sure of that by withdrawing the Treaty from the Senate in January 1980. Salt-II was signed, but was not ratified. In the 1980s, the two nations agreed to abide by the agreement until new arms negotiations could take place. Strategic Arms Reduction Treaty (START) II: Signed in 1993 Status: Never entered into force Start II should complete START I instead of replacing it. Start II has set a limit for strategic weapons, with reductions to be implemented in two phases. By the end of Phase I, the United States and Russia are expected to reduce their total strategic nuclear warheads to 3,800-4.250 and 3,000-3,500 by the end of Phase II.
Phase II also required the elimination of all heavy ICBMs and ICBMs on MIRVs. The resulting set of agreements (SALT I) included the Ballistic Missile Systems (ABM) Treaty and the Interim Agreement and Protocol on the Limitation of Strategic Offensive Weapons. Both were signed by President Richard M. Nixon for the United States and Leonid Brezhnev, General Secretary of the Communist Party of the Soviet Union, for the U.S.S.R. on May 26, 1972 at a summit in Moscow. 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.  New Strategic Arms Reduction Treaty (START): Signed in 2009 Status: still in force, February 5, 2021, unless extended by the United States and Russia In 2009, U.S. President Barack Obama and Russian President Dmitry Medvedev New START, a sequel to START I, expired in December 2009. New START limits both parties to 1,550 nuclear warheads used; 700 ICBMs, submarine-launched ballistic missiles and nuclear bombers; and a total of 800 launchers (provided and not provided). It also provides for inspections and exchange of data on each other`s nuclear arsenals, which were lost during the shutdown of START I in 2009. In November 1972, Washington and Moscow agreed to follow a FOLLOW-up contract of SALT I. SALT II, signed in June 1979, which limited U.S. and Soviet nuclear forces to 2,250 delivery vehicles (defined as ICBM silo, SLBM or heavy bombers) and implemented a multitude of additional restrictions for deployed strategic nuclear forces.
The agreement would have forced the Soviets to reduce their troops by about 270 delivery vehicles, but U.S. forces were below limits and could even have been increased. However, President Jimmy Carter asked the Senate not to consider SALT II after the Soviet Union invaded Afghanistan in December 1979 for its advice and approval, and the treaty was not resumed.