Nuclear Non-Proliferation Treaty. Brought into effect in 1970 by the United Nations to prevent nuclear armament by countries other than the five nuclear-armed countries which are the United States of America, the Soviet Union, France, Britain, and the People's Republic of China. Another purpose of the treaty was the nuclear disarmament of the aforementioned five countries. However, the treaty did not, in fact, have the power to prevent nuclear proliferation as no penalties for treaty violations existed.