Treaty on the Non-Proliferation of Nuclear Weapons

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is the cornerstone of the global nuclear non-proliferation regime. It was opened for signature on 1 July 1968 and entered into force on 5 March 1970. With around 190 states parties, it is one of the most widely adhered-to arms control treaties in history.

The NPT rests on three mutually reinforcing pillars:

• Non-proliferation: Non-nuclear-weapon states (NNWS) commit not to acquire or manufacture nuclear weapons (Articles I and II), and accept International Atomic Energy Agency (IAEA) safeguards on their nuclear material (Article III).
• Disarmament: All parties, particularly the five recognized nuclear-weapon states (NWS) — the United States, Russia (succeeding the USSR), the United Kingdom, France, and China — pledge to pursue negotiations in good faith on effective measures toward nuclear disarmament (Article VI).
• Peaceful uses: Parties have an "inalienable right" to develop nuclear energy for peaceful purposes and to share technology and materials cooperatively (Articles IV and V).

The treaty defines a NWS as one that manufactured and detonated a nuclear device before 1 January 1967, freezing the recognized nuclear club at five. India, Pakistan, and Israel have never joined; North Korea announced its withdrawal in 2003 under Article X, which permits withdrawal on three months' notice if "extraordinary events" jeopardize a party's supreme interests.

Review Conferences are held every five years. The 1995 Review and Extension Conference indefinitely extended the treaty, which had originally been concluded for a 25-year initial term. Subsequent conferences have produced mixed results: the 2000 conference adopted "13 Practical Steps" on disarmament, while the 2005, 2015, and 2022 conferences ended without a consensus final document, reflecting persistent tensions between NWS and NNWS over the pace of disarmament, and disputes involving Iran's safeguards compliance and the Middle East WMD-free zone proposal.