Since nuclear weapons were first used in August 1945, the international community has made great strides to limit the development and deployment of nuclear weapons. Multilateral and bilateral treaties regarding non-proliferation, limitation, and reduction of nuclear weapons have played a valuable role in preventing excessive proliferation of nuclear weapons.
Treaty on the Non-Proliferation of Nuclear Weapons (NPT): The Treaty on the Non-Proliferation of Nuclear Weapons or Nuclear Non-Proliferation Treaty (NPT) is a multilateral treaty concerning the spread of nuclear weapons. It has three major provisions. One, states without nuclear weapons cannot acquire them. Two, nuclear weapon states must pursue disarmament. And three, states can access nuclear technology for peaceful purposes, such as nuclear energy, with proper safeguards. The treaty opened for signature in 1968 and entered into force two years later.
The treaty recognized five states as nuclear weapon states: China; France; Russia; the United Kingdom; and the United States. Neither India, Pakistan, nor Israel signed the treaty. India and Pakistan both acknowledge their possession of nuclear weapons, while Israel maintains a policy of nuclear ambiguity. North Korea, on the other hand, did sign the treaty, but formally withdrew in January 2003, three years before its first nuclear weapon test.
Anti-Ballistic Missile Treaty and Strategic Arms Limitation Talks/Treaty (SALT) I and II: In January 1967 President Lyndon B. Johnson announced that the Soviet Union was building a limited Anti-Ballistic Missile (ABM) defense system. An ABM would potentially give one side the ability to launch a first strike while preventing opposing missiles from entering its airspace. Deterrence theory suggests that this imbalance would limit the efficacy of nuclear deterrence.
Consequently, Johnson called for Strategic Arms Limitation Talks with the Soviet Union. He met with Soviet Premier Alexei Kosygin at Glassboro State College in New Jersey. Talks continued with Johnson’s successor, Richard Nixon, in 1969. The two sides negotiated for the next two and a half years.
On May 26, 1972, Nixon and Soviet General Secretary Leonid Brezhnev signed two bilateral treaties: the ABM Treaty and an interim SALT agreement (known as SALT I). The ABM Treaty limited each state to maintain 200 interceptor missiles and to construct two missile defense sites. The SALT agreement limited the number of nuclear armed missiles in each state's arsenals.
However, this SALT agreement had limitations. Most notably, it only limited the number of missiles each state could possess. It not prevent either state from developing and deploying Multiple Independently Targeted Re-Entry Vehicles (MIRVs), which allowed multiple nuclear warheads to be launched on a single missile.
Therefore, a second round of SALT began negotiations in late 1972. Negotiations for SALT II continued through the Ford and Carter administrations. In November 1974, Ford and Brezhnev had a summit meeting in Vladivostok in eastern Russia. At this meeting, the two leaders agreed on the basic framework of a SALT II agreement. Both states would each be limited to 2,400 strategic nuclear delivery vehicles—Intercontinental Ballistic Missiles (ICBMs), Submarine Launched Ballistic Missiles (SLBMs), and heavy bombers—and 1,320 MIRV systems. Negotiations lasted for another five years. Carter and Brezhnev signed the SALT II Treaty on June 17, 1979 in Vienna. The final agreement further limited delivery vehicles to 2,250 vehicles.
Strategic Arms Reduction Treaty (START I) and Intermediate-Range Nuclear Forces (INF) Treaty: During the 1980 presidential campaign, Ronald Reagan was critical of SALT II. Though he agreed to abide by it until its expiration in 1985, Reagan pursued a new nuclear agreement. Negotiations for an agreement on comprehensive reductions in nuclear weapons rather than limitations began in May 1982. However, negotiations paused in November 1983 after the United States deployed intermediate-range missiles in Europe.
In January 1985 Secretary of State George Schultz and Soviet Foreign Minister Andrey Gromyko agreed to begin negotiations discussing strategic weapons, intermediate-range forces, and missile defense. In December 1987 the United States and the Soviet Union signed the Intermediate-Range Nuclear Forces (INF) Treaty. This treaty requires ground launched ballistic missiles with ranges between 500 and 5,500 kilometers to be destroyed. Both states fully complied with the treaty by May 1991. In 2019, amid accusations of Russian violations of the treaty, the US announced it would withdraw from the agreement. In retaliation, Russia officially withdrew from the treaty as well.
U.S.-Soviet negotiations on strategic arms reduction and missile defense were complicated in late 1985 when Reagan reinterpreted the ABM Treaty to allow research into space-based missile defense systems. This allowed him to pursue the Strategic Defense Initiative (SDI). In January 1986 Soviet General Secretary Mikhail Gorbachev announced a plan for full nuclear disarmament of the two states by the year 2000, contingent on the United States abandoning SDI.
However, negotiations continued. While the basic provisions of START I were agreed upon, the treaty was delayed by the dissolution of the Soviet Union. Russia, Belarus, Kazakhstan, and Ukraine were recognized as parties to the treaty in place of the Soviet Union, though only Russia was recognized by the NPT as a nuclear weapon state. START I entered into force after all of this on December 5, 1994. It limited each state to 1,600 delivery vehicles and 6,000 warheads. A second START Treaty, which banned the use of MIRVs, was signed in 1993 by Russia and the United States, but never went into effect. A third START Treaty was negotiated but never signed.
Strategic Offensive Reductions Treaty (SORT): The United States and Russia met at a summit meeting in Moscow and St. Petersburg in May 2002 to discuss a variety of issues including energy, information technologies, and economic issues. The two countries also discussed nuclear weapons. While the United States did not believe a new treaty was necessary at this point, Russia insisted.
The United States and Russia signed the Strategic Offensive Reductions Treaty (SORT) on May 24, 2002. On June 1, 2003 SORT entered into force. Under SORT, the two parties agreed to reduce and limit strategic nuclear warheads to 1,700 to 2,200 by December 31, 2012. Further, the treaty reaffirmed both states commitment to START I. SORT's reduction targets were superseded by New START.
New START: The Treaty between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms or New START was signed in April 2010 and entered into force in February 2011.
New START limits each party to 1,550 deployed nuclear warheads. The Treaty also includes a limit of 800 deployed and non-deployed ICBM launchers, SLBM launchers, and heavy bombers equipped for nuclear armaments. In addition, no more than 700 ICBMs, SLBMs, and heavy bombers can be deployed. In accordance with the treaty, these provisions must be met by February 5, 2018.