Module 1:

What Is It? Why Is It Important?

Updated: 2023

Select a Treaty

  • Ratified
  • Required for Entry into Force
  • Hague Code of Conduct
  • Conference on Disarmament
  • IAEA member states
  • Withdrawn
  • Missile Technology Control Regime
  • Mongolian Nuclear-Weapons Free Status
  • Treaty of Bangkok — Treaty on the Southeast Asia Nuclear Weapon-Free
  • Treaty of Pelindaba — African Nuclear-Weapon-Free Zone Treaty
  • Treaty of Rarotonga — South Pacific Nuclear Free Zone Treaty
  • Treaty of Tlatelolco — Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean
  • Treaty on a Nuclear-Weapon-Free Zone in Central Asia
  • European Union
  • League of Arab States
  • New Agenda Coalition
  • Non-Aligned Movement
  • Nonproliferation and Disarmament Initiative
  • Observer States to NAM
  • Vienna Group of 10
  • Proliferation Security Initiative
  • Countries with voluntarily terminated nuclear weapons research or production programs
  • Non-Members
  • Non-Nuclear Weapon State Members
  • Nuclear sharing states
  • Nuclear Weapon State (NWS) members
  • Other nuclear-weapon possessing states
  • Withdrawn

The map above outlines participation in nonproliferation treaties and organizations, highlighted by country. The five treaties and organization types (above) describe prominent forces in the international nonproliferation regime. Selecting a treaty or organization type from the drop-down menu in the upper left-hand corner of the map and then selecting a country on the map will display information about that country's membership in the relevant treaty or organization.

What is the nuclear nonproliferation regime?

The nuclear nonproliferation regime is a broad international framework of agreements and organizations aimed at preventing the spread of nuclear weapons and contributing to arms control and disarmament progress. Fears that the Cold War arms race was spiraling out of control led to the initial establishment of the regime, intended to promote stability and reduce the likelihood of nuclear weapons use.

The nuclear nonproliferation regime consists of:

  • International treaties
  • Multilateral and bilateral agreements
  • Voluntary (non-binding) agreements
  • International organizations
  • Domestic agencies, laws, regulations, and policies of participating countries (necessary for regime compliance).

The nuclear nonproliferation regime’s components serve to:

  • Create legally binding nonproliferation obligations
  • Strengthen international norms against the spread of nuclear weapons
  • Control access to nuclear weapons-relevant materials and technologies
  • Build trust between states by verifying compliance with treaty commitments
  • Enforce treaties in instances of non-compliance.

Many of the regime’s components address several nonproliferation goals at once, and mutually reinforce one another. For example, the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) requires nuclear materials in non-nuclear weapon states to be placed under IAEA safeguards. However, neither the NPT nor the IAEA is capable of interdicting illicit nuclear materials trafficking, so voluntary agreements such as the Proliferation Security Initiative have come into existence to help address gaps in the regime. Additionally, more recent agreements like the 2017 Treaty on the Prohibition of Nuclear Weapons take the NPT a step further, establishing legal frameworks for the verified, time-bound elimination of nuclear weapons programs and extending the NPT requirement for safeguards. [1] The extensive network of treaties, agreements, and organizations in the nonproliferation regime strengthens nonproliferation norms, builds trust between states, and forms a web of proliferation prevention.

Why is the nonproliferation regime important?

The humanitarian, economic, and environmental consequences of nuclear war are unimaginable. While the likelihood of a full-scale nuclear exchange has decreased significantly since the U.S.-Soviet Cold War, the continued existence of about 12,500 nuclear warheads poses ongoing risks of intentional, accidental or unauthorized nuclear weapons use. [2] Preventing the spread of nuclear weapons, and working toward the reduction and eventual elimination of existing nuclear arsenals, therefore benefits all members of the international community.

By the mid-1960s, five countries had developed and tested nuclear weapons. Policymakers and analysts feared a chain reaction of nuclear proliferation, with President John F. Kennedy famously observing in 1962: “I see the possibility in the 1970s of the president of the United States having to face a world in which 15 or 20 or 25 nations may have these weapons.” [3]

Today, only nine countries possess nuclear weapons. From a Cold War height of approximately 64,449 nuclear warheads, the world’s nuclear arsenals have decreased to roughly 12,500 warheads. [4] Worst-case scenarios have been avoided in no small part thanks to the development of the nuclear nonproliferation regime, whose extensive network of treaties, organizations and non-binding agreements have aided in the development and implementation of nonproliferation, arms control, and disarmament measures.

However, the work is far from over – with Russia’s thinly veiled threats to use nuclear weapons in the war in Ukraine, China’s expansion of its nuclear capabilities, and North Korea’s intensified long range missile testing, the nuclear risk has dramatically increased since the start of the 2020s. [5] Despite its success since the Cold War, the nuclear nonproliferation regime may have yet to face its greatest test.

[1] International Campaign to Abolish Nuclear Weapons (ICAN), “How the TPNW Complements, Reinforces, and Builds On the NPT,” March 2023. https://assets.nationbuilder.com/ican/pages/3204/attachments/original/1679360844/Briefing_Note_on_NPT-TPNW_Complementarity.pdf?1679360844

[2] “World Nuclear Stockpile Report,” Ploughshares Fund, Updated 15 June 2021. http://ploughshares.org/world-nuclear-stockpile-report

[3] Allison, Graham. “Nuclear Disorder: Surviving Atomic Threats.” Foreign Affairs 89.1 (2010): 74-85. Web. https://www.belfercenter.org/publication/nuclear-disorder-surveying-atomic-threats

[4] Kristensen, Hans and Robert Norris. “Global nuclear weapons inventories, 1945-2013,” Bulletin of the Atomic Scientists, 13 October 2013. http://thebulletin.org/2013/september/global-nuclear-weapons-inventories-1945-2013.

[5] “An exceedingly dangerous nuclear situation,” Bulletin of the Atomic Scientists, 24 January 2023. https://thebulletin.org/doomsday-clock/current-time/nuclear-risk/