The events of July 7, 2017 at the United Nations in New York deserve our attention. The Treaty on the Prohibition of Nuclear Weapons (TPNW) constitutes a real paradigm shift, and the end of a period of stagnation in nuclear disarmament of more than 20 years. After biological (1972) and chemical weapons (1993), the remaining type of weapons of mass destruction will be banned once the treaty enters into force.

Even though there is considerable disagreement on the practical implications of the treaty for nuclear disarmament and international security, its significance has been confirmed by the fact that the International Campaign to Abolish Nuclear Weapons (ICAN), the coalition that was instrumental in the negotiation and adoption of the treaty, was awarded the 2017 Nobel Peace Prize.

End of March 2018, 57 States have signed the TPNW and 7 have ratified it
so far. 50 ratifications will be necessary for the treaty to enter into force.
Once in force, it will reinforce the norm against nuclear weapons, create new momentum for nuclear disarmament, give civil society a new tool in its fight for a world free from nuclear weapons, and put more pressure on Nuclear Weapons States (NWS) and their allies.

The new instrument is a “treaty” in the sense of the 1969 Vienna Convention on the Law of Treaties (VCLT), namely an “international agreement concluded between States in written form and governed by international law (…)”. 1 As such, it is quite a complex construction that will certainly raise many questions of interpretation during its hopefully long life. The present short article-by-article commentary is intended to facilitate understanding of the new treaty, without going into great legal detail. It is intended for a general audience, including persons not possessing deep knowledge of international law. We hope it will stimulate debate about this new instrument, inform representatives of civil society, teach young people and students, and assist diplomats and State agents in their work towards ratification of the treaty.