The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is a multilateral international treaty that serves as the cornerstone of the global nuclear non-proliferation regime. It was opened for signature on July 1, 1968, and entered into force on March 5, 1970. The treaty was created to solve the problem of potential widespread nuclear proliferation, which was a major concern during the Cold War, with some experts fearing a world with 25 or more nuclear-armed states.
The NPT is based on a "grand bargain" structured around three mutually reinforcing pillars: non-proliferation, disarmament, and the peaceful use of nuclear energy. It divides its 191 states parties into two categories: Nuclear-Weapon States (NWS) and Non-Nuclear-Weapon States (NNWS). The NWS are defined in Article IX as those that manufactured and exploded a nuclear device prior to January 1, 1967, which are the United States, Russia, the United Kingdom, France, and China.
The treaty works through key provisions: Article I prohibits NWS from transferring nuclear weapons or technology to any recipient, and Article II obligates NNWS to forgo developing or acquiring nuclear weapons. Article III requires NNWS to accept comprehensive international safeguards, which are administered by the International Atomic Energy Agency (IAEA), to verify that nuclear material is not diverted from peaceful uses. Article IV affirms the "inalienable right" of all parties to research and use nuclear energy for peaceful purposes and promotes the exchange of related technology. Crucially, Article VI commits all parties, especially the NWS, to pursue good-faith negotiations on effective measures for nuclear disarmament.
The NPT is connected to the IAEA, which verifies compliance, and the Comprehensive Nuclear Test Ban Treaty (CTBT), which has rendered Article V (on peaceful nuclear explosions) effectively obsolete. The treaty was originally set for a 25-year duration but was indefinitely extended in 1995. The treaty's operation is reviewed every five years at a Review Conference. No recent amendments have replaced the core provisions, as Article VIII requires a complex process for change, but the Additional Protocol to the IAEA safeguards has strengthened verification measures since 1997. India, along with Israel, Pakistan, and South Sudan, remains outside the NPT.