Proposed Nuclear Weapons Ban Treaty

The Nuclear Weapons Ban is an initiative to prohibit the use, possession, development, testing, deployment and transfer of nuclear weapons under international law. Unlike prior efforts at comprehensive nuclear disarmament, notably the proposed Nuclear Weapons Convention, a treaty banning nuclear weapons would not include dismantlement and disarmament verification procedures. As such, its proponents argue, the negotiation of a ban treaty does not require the participation of the nuclear weapons possessors.

Advocates of a ban treaty believe that nuclear weapons are incompatible with international law. First, as a consequence of their destructive power and radioactive fallout, nuclear weapons inherently violate several articles of the Geneva Conventions meant to protect the victims of international conflicts. Second, many non-nuclear weapons states and disarmament advocates believe that states possessing nuclear weapons have been unwilling to pursue good-faith negotiations mandated by the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).

Proponents see the nuclear weapons ban treaty as a measure to close this perceived “legal gap” in international law, and to encourage an international norm against nuclear weapons. Opponents characterize the initiative as unrealistic political grandstanding which could weaken the NPT.


Negotiations on a nuclear weapons ban treaty are in progress. The first round of UN negotiations ran from 27-31 March 2017. The UN-backed conference released a draft Convention on the Prohibition of Nuclear Weapons on 22 May, 2017. The second round will take place from 15 June to 7 July, 2017.


Efforts to outlaw nuclear weapons date to the beginning of the atomic age. However, the current nuclear weapons ban project has its origins in the Humanitarian Initiative, a group of non-nuclear weapons states who have sought to push nuclear disarmament forward by focusing on the severe humanitarian consequences of nuclear war.  As the movement gained support among the international community, backers of the Humanitarian Initiative had high hopes that the 2015 Review Conference on the Nonproliferation of Nuclear Weapons (NPT) would achieve substantial progress toward nuclear disarmament.

Although 160 states endorsed the Humanitarian Initiative at the 2015 NPT Review Conference, the conference failed to adopt a consensus final document. Many countries were dissatisfied with this outcome, and sought to shift efforts to advance the disarmament agenda to an open-ended working group (OEWG) on nuclear disarmament within the United Nations General Assembly. For many advocates of nuclear disarmament, the UN General Assembly was a preferable negotiating forum, as it reaches decision by a majority vote of member states rather than consensus.

At the three open-ended working group meetings in Geneva in 2016, participating states discussed strategies for moving the nuclear disarmament agenda forward. Many states, such as Algeria, Brazil, Indonesia, and South Africa, spoke in favor of opening negotiations for a ban treaty, while nuclear-reliant states present opposed this approach to disarmament, speaking in favor of a “building-blocks,” or “progressive,” approach. The proponents of a ban were victorious, and  at the third session of the OEWG, States voted to adopt the final report recommending the UN General Assembly convene a conference in 2017 to prohibit nuclear weapons. The vote was 68-22, with 13 countries abstaining. All nine states possessing nuclear weapons boycotted the OEWG, and all dissenting votes came from allies of the United States. The U.S., which did not attend the OEWG sessions, rejected the final report, calling such efforts to ban nuclear weapons “unrealistic.”

On 27 October, 2016, The First Committee of the General Assembly adopted resolution A/C.1/71/L.41 to convene negotiations on a nuclear weapons ban in 2017, and the full General Assembly approved the resolution on 23 December 2016. Opening negotiations took place in New York from 27-31 March 2017, with a second round scheduled for 15 June – 7 July, 2017.


The draft treaty of 22 May 2017, obligates all State Parties to the prohibition of nuclear weapons possession, development, production, transfer, use, and testing, and of assisting any other state with the same. It also prohibits States Parties from stationing another nation’s nuclear weapons on their territory.

The draft treaty does not create a verification regime. It stipulates that each State Party shall “undertake to accept safeguards” to prevent the diversion of peaceful nuclear technology for weapon purposes, and that former nuclear weapons possessing State Parties shall cooperate with the International Atomic Energy Agency (IAEA) to verify the completeness of their disarmament.

According to the 22 May draft, the nuclear ban treaty will enter into force 90 days after its fortieth instrument of ratification has been deposited. 



On 16 February, states attended the organizational meeting for the March 2017 UN conference to negotiate a nuclear weapons ban. Ambassador Elayne Whyte of Costa Rica was elected as president of the conference. States discussed a draft provisional agenda, conference rules of procedure, and the level of participation to be allowed for non-governmental organizations.

From 27-31 March, the first round of UN negotiations on a nuclear ban treaty took place in New York City. Over 120 countries attended negotiations, however the U.S. led a boycott of several states, including all nine nuclear weapons possessing states. Topics of discussion at the conference included the treaty’s objectives, preambular paragraphs and core prohibitions, as well as its legal and institutional arrangements. While states generally agreed on the broad outlines of what is to be included in the ban treaty, there was disagreement on a number of issues. States were divided over whether or not the ban treaty needs its own verification protocols in addition to those that exist under the NPT. There was disagreement over how to effectively stop nuclear weapons stockpiling and their transit and transshipment. States also diverged on whether or not the treaty should include language banning nuclear testing and prohibiting threatening to use nuclear weapons.

From 2-12 May, the first Preparatory Committee meeting (PrepCom) for the 2020 Nuclear Non-Proliferation Treaty Review Conference was held in Vienna. Several delegations mentioned the ban treaty negotiations in their statements, and the Chair’s factual summary included reference to various States Parties’ views of the proposed treaty. However, observers noted that the proposed ban treaty was the “elephant in the room,” and both proponents and opponents of the ban treaty were hesitant to raise the issue during formal proceedings.

On 22 May, the president of the Conference released the Draft Convention on the Prohibition of Nuclear Weapons based on the first round of negotiations. The draft treaty will be subject to revision at the second round of negotiations in June. 


On 22-26 February, the UN hosted the first session of the second OEWG on concrete legal measures towards a nuclear weapons ban in Geneva, Switzerland. The session addressed possible measures to address the risk posed by an accidental, unauthorized, or intentional detonation of nuclear weapons, as well as the humanitarian risk posed by such a nuclear detonation. 

On 2-13 May, the UN hosted the second session of the second OEWG on legal measures and norms to take towards a nuclear weapons ban in Geneva, Switzerland. The session addressed possible pathways to a legal ban on nuclear weapons, and therefore disarmament. Furthermore, the session addressed nuclear weapons in the context of the 21st century, the issue of transparency, and the humanitarian impact of nuclear detonation.

On 5-19 August, the UN hosted the third session of the second OEWG to establish a legal ban against nuclear weapons in Geneva, Switzerland. The OEWG published a final report outlining several key factors: the importance of NWS to undertake the actions required as stated in the 2000 NPT Review Conference, the importance of further multilateral negotiations, and the lack of guidance regarding the implementation of Article VI of the NPT. The document further provided different legal mechanisms through which the international community could enforce Article VI of the NPT, including a prohibition of weapons, their use, NWFZs, or a new legal ban on nuclear weapons or their use.  

On 13 October, Resolution A/C.1/71/L.41 (L.41) was submitted to the UN General Assembly First Committee. L.41 was originally sponsored by Austria, Brazil, Ireland, Mexico, Nigeria, and South Africa, but counts fifty-seven States as co-sponsors. It was based on recommendations made in the 2016 OEWG report. L.41 does not establish a nuclear ban treaty, but proposes holding negotiations in 2017 on such an instrument.

On 27 October, the UN General Assembly First Committee voted on L.41. States adopted the resolution to hold negotiations on a nuclear ban treaty in 2017. Despite strong opposition on the part of the nuclear-weapon states and their allies, L.41 was adopted with 123 votes in favor, 38 votes against, and 16 abstentions. The resolution set up a UN conference to negotiate a “Legally Binding Instrument to Prohibit Nuclear Weapons” which will take place in March 2017.


On 29 October, the UNGA First Committee voted to hold a second OEWG regarding negotiations on a nuclear weapons ban.

On 7 December, the UNGA adopted Resolution 70/33, establishing a working group to “substantively address concrete effective legal measures, legal provisions and norms that will need to be concluded to attain and maintain a world without nuclear weapons.”


On 13-14 February, the second Conference on the Humanitarian Impact of Nuclear Weapons was held in Nayarit, Mexico. Participants in the conference reiterated their call for the development of new international standards on nuclear weapons, including a legally binding instrument within a specified timeframe.

On 2 April, Ireland submitted a working paper on behalf of NAC at the 2014 Preparatory Committee for the 2015 NPT Review Conference. The paper discussed the implementation of Article VI of the NPT as an “effective measure” to ban nuclear weapons. The paper further mentioned the “need for a clear, legally-binding, multilateral commitment to achieve nuclear disarmament.”

 On 8-9 December, Austria hosted the third Conference on the Humanitarian Impact of Nuclear Weapons in 2014. The Conference looked to strengthen the international nonproliferation and disarmament regime and examined the impacts of intentional or accidental nuclear weapons explosions. Forty three states signed the Austrian Pledge, which recognizes the immediate and long-term consequences of nuclear explosions on health, infrastructure, and the environment and looks to fill the “legal gap” on the prohibition of nuclear weapons. As more states signed on, the Austrian Pledge became the Humanitarian Pledge in May 2015. One hundred and twenty seven states have endorsed the Humanitarian Pledge.


On 2-3 March, the International Campaign to Abolish Nuclear Weapons (ICAN) hosted a civil society forum to demonstrate the humanitarian impact of nuclear weapons use and called upon states to outlaw these weapons.

On 4-5 March, 127 governments, UN agencies, international organizations and members of civil society met in Oslo, Norway to discuss the humanitarian consequences of nuclear weapons use. The first Conference on the Humanitarian Impact of Nuclear Weapons concluded that governments and relief agencies would be unable to adequately respond to the detonation of a nuclear weapon. 


On 3 December, the UN General Assembly adopted Resolution 67/56, convening an open-ended working group to develop proposals to take forward multilateral nuclear disarmament negotiations.


The proposed nuclear weapons ban is an initiative to prohibit the use, possession, development, testing, deployment and transfer of nuclear weapons under international law.

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2017.