The Non Proliferation Treaty (NPT)- 1968- The Treaty has three primary goals: preventing the further spread of nuclear weapons; facilitating international cooperation in the peaceful uses of nuclear energy under International Atomic Energy Agency (IAEA) safeguards; and encouraging negotiations on nuclear arms control.
The treaty distinguishes between two categories of states, nuclear weapon states (NWS) and nonnuclear weapon states (NNWS), and defines separate obligations for states in each of the categories. The treaty obligates the five acknowledged nuclear-weapon states (the United States, Russian Federation, United Kingdom, France, and China) not to transfer nuclear weapons, other nuclear explosive devices, or their technology to any non-nuclear-weapon state. Non-nuclear-weapon States Parties undertake not to acquire or produce nuclear weapons or nuclear explosive devices.
They are required also to accept safeguards to detect diversions of nuclear materials from peaceful activities, such as power generation, to the production of nuclear weapons or other nuclear explosive devices. Another significant aspect of the treaty is stated in article IX which determine what qualifies a state as a nuclear weapon state (NWS).
According to the article the state must have 1) manufactured and 2) exploded a nuclear weapon or other nuclear explosive device 3) before 1 January 1967. The significance of this article is that in affect it prohibits from any of the states party to the NPT, other than the five recognized NWS, from ever becoming NWS.
The Treaty was opened for signature on 1 July 1968, and signed on that date by the United States, the United Kingdom, the Soviet Union, and 59 other countries. The Treaty entered into force with the deposit of US ratification on 05 March 1970. China acceded to the NPT on 09 March 1992, France acceded on 03 August 1992, Argentina 1995, and Brazil 1998.
The NPT is the most widely accepted arms control agreement; only Israel, India, and Pakistan have never been signatories of the Treaty.