On November 24, 1969, the United States and the Soviet Union ratified the Nuclear Non-Proliferation Treaty (NPT) in order to prevent the further spread of nuclear weapons and ultimately create a world free of “the bomb”.
The treaty was born in the Cold War era, when the development of nuclear weapons had reached the stage where any conflict between the nuclear-armed nations could have led to the destruction of not only the opponents, but to every living thing on the planet. After more than a decade of negotiations it was signed by the United States, Britain and the Soviet Union, along with 59 other countries, on July 1, 1968.
US President Lyndon Johnson submitted the NPT to the US Senate for ratification on July 9, 1968, however after the Soviet invasion of Czechoslovakia in August of that year, the Senate refused to approve any agreements with Moscow.
As feelings cooled between the two superpowers in early 1969, the newly-elected US President Richard Nixon re-introduced the document for agreement. The Senate approved it on March 13, 1969 and Nixon signed the NPT into law on November 24, 1969. In March 1970, the treaty came into force as an international legal instrument.
The agreement established that a nuclear weapons state is one which has manufactured and exploded a nuclear explosive device prior to January 1, 1967 (USSR, USA, Britain, France and China). One of the key articles in the NPT prohibited these nuclear powers from transferring nuclear weapons to any recipient and assisting in manufacturing them. The treaty protected the peaceful use of nuclear energy by all states and ensured that nuclear energy was not diverted into nuclear weapons. The sixth article obligated nuclear weapons states to pursue "negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament".
The NPT was subjected to criticism, chiefly due to the inequalities it created between nuclear and non-nuclear states. It was referred to as a “conspiracy” between the two superpowers to preserve the nuclear monopoly of the US and the USSR. North Korea withdrew from the treaty in 2003 and India, Israel and Pakistan remain the only non-signatory states.
Currently, with 189 countries party to the NPT, it remains one of the most significant multilateral arms control achievements of the nuclear age. In May 2010 the NPT Review Conference was held at the UN Headquarters in New York. UN Secretary-General, Ban Ki-Moon, speaking at the opening of the conference noted that "sixty-five years later, the world still lives under the nuclear shadow."