Since the 19th century, world powers have conferred in peacetime about disarmament, believing that to avoid war weapons should be reduced in number or eliminated. A new era in warfare began when the bombing of cities and industry through WORLD WAR II climaxed with the atomic bombing of Hiroshima and Nagasaki, Japan. Many political and scientific leaders began to place disarmament at the head of problems to be solved in order for humanity to have a better future.
Negotiations to prevent nuclear war began in 1946, usually under the auspices of the United Nations. In 1959 Nikita Khrushchev proposed in the UN General Assembly that the nations should commit themselves to complete disarmament. Although this was not achieved by several UN disarmament committees, some measure of "arms control" was reached - eg, the 1963 partial ban on testing nuclear weapons and the 1968 Non-Proliferation Treaty. Meanwhile, since the race to build intercontinental missiles continued, the superpowers in 1969 decided to hold strategic arms limitation talks by themselves. A treaty, SALT I, came into force in 1972. A second, SALT II, was rejected by the US Senate.
During the Cold War NATO feared that the Warsaw Treaty nations (the USSR and its eastern European allies) would have superiority in conventional weapons (guns, tanks, attack aircraft), which would allow them to invade western Europe, sweeping aside the defending conventional forces. Until the 1970s the US was believed to have superiority in intercontinental aircraft and missiles so that it could deter any conventional attack by the threat of nuclear destruction, which it could visit on the USSR and its allies without incurring corresponding damage. However, with a change through the 1970s in the balance of intercontinental armaments, the theory of graduated response was evolved. An invasion by conventional forces would be met by limited response with nuclear weapons of theatre range, the threat of escalation causing the combatants to cease hostilities.
Because Canada helped produce the atomic bomb, it has participated in disarmament talks since the beginning, advocating mutually balanced, verifiable disarmament. But Canada's freedom of expression has been limited by the need for solidarity within NATO. The government's concerns, shared by an increasing number of Canadians in the 1980s, included global destruction, the strategic implications of a nuclear war between the superpowers (because of Canada's geographical location) and damage to delicate environments such as the Arctic, Great Lakes and coasts caused by the testing of nuclear weapons or war. International conferences on arms control continued into the late 1980s. As part of the ongoing negotiations between US President Reagan and Soviet leader Gorbachev, a treaty was signed 8 December 1987 providing for the eventual removal of intermediate-range missiles, the first agreement to eliminate an entire class of nuclear weapons. See also ARMAMENTS; PACIFISM; WOMEN'S INTERNATIONAL LEAGUE FOR PEACE AND FREEDOM; PEACE MOVEMENT.