Module 2:

International Treaties

What is a treaty?

A treaty is a formal, written agreement between sovereign states or between states and international organizations. Treaties:

  • Establish and enforce norms (e.g., how states will behave relating to the development or use of nuclear weapons)
  • Create international law, binding state parties to certain obligations
  • May contain verification mechanisms to ensure states are in compliance with treaty obligations (e.g., inspections)
  • May contain enforcement mechanisms to create disincentives for non-compliance (e.g., referral of the state to the United Nations Security Council).

What are the nuclear nonproliferation regime’s primary treaties?

What is the Treaty on the Non-Proliferation of Nuclear Weapons (NPT)?

Considered the cornerstone of the nuclear nonproliferation regime, the NPT embodies the international community’s efforts to prevent the further spread of nuclear weapons, and to cooperate in achieving a world free of these weapons. It also facilitates states’ pursuit of nuclear energy for peaceful purposes, and through the International Atomic Energy Agency (IAEA), has an extensive verification regime to ensure that non-nuclear-weapon states are in compliance with their obligations not to develop or obtain nuclear weapons.

  • Opened for signature July 1, 1968
  • Entered into force on March 5, 1970
  • Initial duration of 25 years; state parties at the 1995 Review and Extension Conference agreed to indefinite extension

Through its three pillars of nonproliferation, disarmament, and peaceful uses, the NPT:

  • Prohibits the non-nuclear weapon states from developing or acquiring nuclear weapons
  • Prohibits the five treaty-recognized nuclear-weapon states from transferring nuclear weapons to the non-nuclear weapon states
  • Facilitates access to peaceful uses of nuclear technology for all non-nuclear-weapon states in compliance with the treaty and their IAEA safeguards obligations
  • Uses IAEA safeguards to monitor peaceful uses of nuclear materials and technology in the non-nuclear weapon states, thereby detecting and deterring diversion to an illicit nuclear weapons program
  • Commits all member states to pursue good faith negotiations toward ending the nuclear arms race and achieving nuclear disarmament.

For more information, please see the NPT Tutorial.

Which treaties restrict or ban nuclear testing, and why?

  • The nuclear-weapon possessing states have conducted more than 2,000 tests since 1945 to assess and improve the capabilities of their arsenals[i]
  • Test bans support arms control and nonproliferation objectives by making it difficult for new states to develop reliable nuclear weapons, and for the existing nuclear weapon-possessing states to enhance their arsenals’ capabilities
  • Support for a Partial Test Ban Treaty (PTBT) in 1963 was largely possible because of worldwide concern about the detrimental human health and environmental effects of atmospheric and underwater testing

Partial or Limited Test Ban Treaty (PTBT or LTBT)

Prohibits nuclear tests in the atmosphere, outer space, underwater, and anywhere radioactive debris would end up outside the territory of the state conducting the test

The Comprehensive Nuclear Test Ban Treaty (CTBT)

Prohibits all nuclear weapons testing

  • Negotiated from 1993 to 1996 at the Conference on Disarmament (CD); opened for signature in September 1996
  • Will enter into force 180 days after 44 “Annex 2” states have ratified the treaty:
    • North Korea, India, and Pakistan have not yet signed or ratified
    • China, Egypt, Iran, Israel, and the United States have signed but not yet ratified.

How will the international community monitor compliance with the CTBT?

  • The Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization maintains a worldwide test detection network, named the International Monitoring System (IMS)
  • The IMS’s detection capabilities include seismic, infrasound, hydroacoustic, and radionuclide analysis:
    • Seismic monitors detect seismic event signatures; nuclear weapons test signatures are distinguishable from earthquakes and background activity
    • Infrasound monitors search for atmospheric pressure differences caused by the movement of infrasound waves, such as those released by above-ground nuclear tests
    • Hydroacoustic monitors search for the distinct sound waves caused by underwater nuclear detonations
    • Radionuclide stations collect the small particles released by nuclear testing (e.g., xenon-133), and analysis helps to determine whether the particles collected are indicative of nuclear testing vs. other nuclear activities
  • Currently, 275 of the planned 321 monitoring stations and 11 of the 16 radionuclide laboratories are online and have been certified
  • Following entry-into-force, the CTBT provides for additional verification through on-site inspection as necessary.

How do Nuclear-Weapon-Free Zone treaties contribute to the regime?

  • Nuclear-Weapon-Free Zones (NWFZs) are legally binding agreements between states that prohibit the development, manufacturing, control, possession, testing, stationing, and transportation of nuclear weapons within their geographical territories
  • Article VII of the NPT recognizes the right for states to establish NWFZs in their regions
  • Nuclear weapon states (NWS) are prohibited from testing, transporting, transferring, or stationing nuclear weapons in NWFZs
  • Non-nuclear weapon states in NWFZs are not permitted to host nuclear weapons belonging to the NWS
  • Five regional NWFZs have entered into force:
  • Mongolia is the only single-state NWFZ
  • Three NWFZs based on “geographical limitations” exist:

What treaties are currently being negotiated, debated, or discussed?

Proposed Fissile Material (Cut-Off) Treaty, or FM(C)T

  • Main objectives
    • The treaty would ban the production of fissile material for nuclear weapons purposes
    • Many non-nuclear-weapon states argue that the future treaty should cover all existing stocks of fissile materials in military programs, while nuclear weapons states support only the cut-off of future fissile materials production
    • Would require each party to agree to convert, disable, decommission, and possibly dismantle existing facilities producing fissile material for weapons purposes
    • States possessing nuclear weapons will have to accept safeguards or other international controls on fuel cycle facilities to ensure that materials produced there are not used for nuclear weapons or other explosive devices
    • Would establish an FM(C)T organization to implement the treaty.
  • Current status
    • Will be debated in the Conference on Disarmament (CD) once a program of work is adopted by member states
    • The CD has not been able to  commence FM(C)T negotiations since 1996
    • Pakistan has been blocking the adoption of a program of work that would allow the negotiations to start, insisting that the negotiation mandate should include existing stocks, and that nuclear disarmament negotiations should begin in a parallel committee at the CD
  • History
    • Discussion on a cut-off for production of fissile material began in the 1960s
    • From early 1994 through mid-1995, the CD prepared for the formation of an Ad Hoc Committee to begin negotiations on an FM(C)T, but the Committee was never formed.
  • Challenges
    • How to unblock the CD and commence negotiations
    • How to include existing stockpiles of fissile material
    • How an FM(C)T would be verified
    • How to obtain buy-in from countries that produce fissile material for nuclear weapons but have not signed the NPT (India, Israel and Pakistan).

Proposed Treaty on Negative Security Assurances (NSA)

  • Main objectives
    • Nuclear weapon states would conclude arrangements to assure non-nuclear-weapon states that they will not use or threaten the use of nuclear weapons against them (including by revising domestic policies and military doctrines appropriately)
    • Nuclear weapon states have made non-binding or qualified negative security assurances; non-nuclear weapon states want these promises codified into a legally binding, unconditional, universal free-standing treaty or protocol to the NPT
    • Nuclear weapon states have provided legally-binding negative security assurances to some of the NWFZs
  • Current status
    • Issue remains on the permanent agenda of the Conference on Disarmament (CD), but no progress has been made due to the deadlock therein.
  • History
    • The first legally-binding negative security assurance was contained in the Treaty of Tlatelolco, and all five nuclear weapon states have ratified the protocol containing this provision
    • Since the 1960s, the non-nuclear weapon states have called upon the nuclear weapon states to commit to legally-binding negative security assurances
    • The United States has not ratified the NSA protocol to any NWFZ treaty except Tlatelolco, and none of the nuclear weapon states has signed the protocols to the Treaties of Bangkok and Central Asian NWFZ
    • In 1978, each NWS issued unilateral, non-binding assurances, some of which had qualifications attached
  • Challenges
    • Debate over whether legally binding negative security assurances should be negotiated as a new treaty at the CD or in the context of the NPT review process
    • Nuclear weapon states see NSAs as weakening the theory and practice of deterrence and currently do not support the negotiation of an NSA treaty

Proposed Nuclear Weapons Convention (NWC)

  • Main objectives
    • Prohibit all states from pursuing or participating in the possession, development, testing, production, stockpiling, transfer, use and threat of use of nuclear weapons
    • Supplement existing treaties like the Treaty on the Nonproliferation of Nuclear Weapons (NPT) and the Comprehensive Nuclear-Test-Ban Treaty (CTBT)
    • Obligate states possessing nuclear weapons to destroy their arsenals in five phases:
      1. Taking nuclear weapons off alert
      2. Removing weapons from deployment
      3. Removing nuclear warheads from their delivery vehicles
      4. Disabling the warheads, and removing and disfiguring the “pits”
      5. Placing the fissile material under international control.
    • Mandate the destruction or conversion of any nuclear-related delivery vehicles
    • Create an implementation and verification organization called the Agency for the Prohibition of Nuclear Weapons
  • Current status
    • Has been brought up at the Conference on Disarmament (CD) and the United Nations (UN)
    • Costa Rica and Malaysia submitted a draft convention to the United Nations in 2007
  • History
    • Initiative to ban all nuclear weapons dates back to the earliest days of the Cold War
    • United Nations has been evaluating the feasibility of such a ban since the end of the Cold War
    • International Court of Justice found in 1996 that states have a legal obligation to “pursue in good faith and bring to a conclusion negotiations” banning nuclear weapons production and use
    • In 2012, 146 states, including China, India, Pakistan, and North Korea, called for “commencing multilateral negotiations leading to an early conclusion of a nuclear weapons convention prohibiting the development, production, testing, deployment, stockpiling, transfer, threat or use of nuclear weapons and providing for their elimination.”[ii] China has since qualified its support, but India, Pakistan, and North Korea have not
  • Challenges
    • NWS argue that calls for an NWC divert attention from the specific disarmament steps outlined in the NPT context
    • France, Russia, the United Kingdom, and the United States oppose an NWC, and their support would be necessary to its success.


[i] Fedchenko, Vitaly, and Ragnhild Ferm Hellgren. “Appedix 12B. Nuclear explosions, 1945-2006.” Stockholm International Peace Research Institute. 30 August 2007. Web.

[ii] “General and complete disarmament: follow-up to the advisory opinion of the International Court of Justice on the Legality of the Threat or Use of Nuclear Weapons.” United Nations General Assembly  Sixty-sixth session, First Committee working paper. 17 October 2011.