UN Adopts New Treaty on the Prohibition of Nuclear Weapons

The new UN Treaty on the Prohibition of Nuclear Weapons is an important step towards delegitimizing nuclear war as an acceptable risk of modern civilization. Though the treaty will not have the power to eliminate existing nuclear weapons, it provides a vision of a safer world, one that will require great purpose, persistence, and patience to make a reality. Nuclear catastrophe is one of the greatest existential threats facing society today, and we must dream in equal measure in order to imagine a world without these terrible weapons.
The UN treaty places a strong moral imperative against possessing nuclear weapons and gives a voice to some 120 non-nuclear weapons states who are equally affected by the existential risk of nuclear weapons. There is no one solution to this global threat, and there is much more work to be done beyond this treaty to reduce this risk. I call on nuclear-armed states to step up their participation in the fight against the nuclear threat by securing the eight remaining ratifications to enact the Comprehensive Test Ban Treaty, extending the New START agreement, continuing the critical work of the Nuclear Security Summits, and avoiding the unnecessary risk posed by introducing destabilizing new nuclear weapons. My hope is that this treaty will mark a sea change towards global support for the abolition of nuclear weapons. This global threat requires unified global action.
William J. Perry, Former Secretary of Defense
July 7, 2017


Comprehensively bans nuclear weapons and related activity. It will be illegal for parties to undertake any activities related to nuclear weapons. It bans the use, development, testing, production, manufacturing, acquiring, possession, stockpiling, transferring, receiving, threatening to use, stationing, installation, or deploying of nuclear weapons.  [Article 1]

Bans any assistance with prohibited acts. The treaty bans assistance with prohibited acts, and should be interpreted as prohibiting states from engaging in military preparations and planning to use nuclear weapons, financing their development and manufacture, or permitting the transit of them through territorial waters or airspace. [Article 1]

Creates a path for nuclear states which join to eliminate weapons, stockpiles, and programs. It requires states with nuclear weapons that join the treaty to remove them from operational status and destroy them and their programs, all according to plans they would submit for approval. It also requires states which have other country’s weapons on their territory to have them removed. [Article 4]

Over 3700 scientists have signed an open letter supporting the UN negotiations to ban nuclear weapons, including former US Secretary of Defense William Perry, 30 Nobel Laureates & many nuclear experts. 

Verifies and safeguards that states meet their obligations. The treaty requires a verifiable, time-bound, transparent, and irreversible destruction of nuclear weapons and programs and requires the maintenance and/or implementation of international safeguards agreements. The treaty permits safeguards to become stronger over time and prohibits weakening of the safeguard regime. [Articles 3 and 4]

Requires victim and international assistance and environmental remediation. The treaty requires states to assist victims of nuclear weapons use and testing, and requires environmental remediation of contaminated areas. The treaty also obliges states to provide international assistance to support the implementation of the treaty. The text requires states to join the Treaty, and to encourage others to join, as well as to meet regularly to review progress. [Articles 6, 7, and 8]


Opening for signature. The treaty will be open for signature on 20 September at the United Nations in New York. [Article 13]

Entry into force. Fifty states are required to ratify the treaty for it to enter into force.  At a national level, the process of ratification varies, but usually requires parliamentary approval and the development of national legislation to turn prohibitions into national legislation. This process is also an opportunity to elaborate additional measures, such as prohibiting the financing of nuclear weapons. [Article 15]

First meeting of States Parties. The first Meeting of States Parties will take place within a year after the entry into force of the Convention. [Article 8]


Delegitimizes nuclear weapons. This treaty is a clear indication that the majority of the world no longer accepts nuclear weapons and do not consider them legitimate weapons, creating the foundation of a new norm of international behaviour.

Changes party and non-party behaviour. As has been true with previous weapon prohibition treaties, changing international norms leads to concrete changes in policies and behaviours, even in states not party to the treaty. This is true for treaties ranging from those banning cluster munitions and land mines to the Convention on the law of the sea. The prohibition on assistance will play a significant role in changing behaviour given the impact it may have on financing and military planning and preparation for their use.

Completes the prohibitions on weapons of mass destruction. The treaty completes work begun in the 1970s, when Chemical weapons were banned, and the 1990s when biological weapons were banned.

Strengthens International Humanitarian Law (“Laws of War”). Nuclear weapons are intended to kill millions of civilians – non-combatants – a gross violation of International Humanitarian Law. Few would argue that the mass slaughter of civilians is acceptable and there is no way to use a nuclear weapon in line with international law. The treaty strengthens these bodies of law and norm.

Remove the prestige associated with proliferation. Countries often seek nuclear weapons for the prestige of being seen as part of an important club. By more clearly making nuclear weapons an object of scorn rather than achievement, their spread can be deterred.

FLI sought to increase support for the negotiations from the scientific community this year. We organized an open letter signed by over 3700 scientists in 100 countries, including 30 Nobel Laureates. You can see the letter here and the video we presented recently at the UN here.

This post is a modified version of the press release provided by the International Campaign to Abolish Nuclear Weapons (ICAN).