Negative Security Assurance Pledge

A negative security assurance (NSA) is a unilateral or multilateral pledge by a nuclear-weapon state (NWS) not to employ, or threaten to employ, nuclear weapons against non-nuclear-weapon states (NNWS). The concept emerged in the 1960s as a concession sought by NNWS during negotiations for the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), which entered into force in 1970. Many non-nuclear states argued that renouncing nuclear weapons under the NPT entitled them to protection against nuclear coercion in return.

The first formal NSAs were issued in 1978 at the UN General Assembly's First Special Session on Disarmament, when the United States, United Kingdom, and Soviet Union offered separate declarations. These were updated and reiterated in 1995 ahead of the NPT Review and Extension Conference. That same year, the UN Security Council adopted Resolution 984 (1995), which took note of the assurances issued by the five recognized NWS (China, France, Russia, the UK, and the US).

NSAs vary significantly in scope and conditionality:

• China has maintained the broadest pledge, declaring it will never use nuclear weapons against NNWS or in nuclear-weapon-free zones, without explicit caveats.
• The United States, in its 2010 and 2022 Nuclear Posture Reviews, conditioned its NSA on the recipient state being in compliance with its nuclear non-proliferation obligations.
• Russia, the UK, and France have attached caveats permitting nuclear use in response to attacks carried out in alliance with a nuclear-armed state.

Legally binding NSAs exist through protocols to nuclear-weapon-free zone treaties such as Tlatelolco (Latin America), Rarotonga (South Pacific), Pelindaba (Africa), Bangkok (Southeast Asia), and Semipalatinsk (Central Asia), though some NWS have signed these protocols with reservations or not at all. NNWS continue to press for a universal, legally binding NSA instrument, a recurring agenda item in the Conference on Disarmament.