The Treaty on the Prohibition of Nuclear Weapons - A Silver Lining in the Mushroom Cloud?

Abstract: As the Treaty on the Prohibition of Nuclear Weapons (TPNW) entered into force on 22 January 2021, a new legal instrument regulating nuclear weapons entered the international arena. With considerations of the humanitarian and environmental consequences of the use of nuclear weapons, the new Treaty aims for the total elimination of nuclear weapons. In order to accomplish its high ambitions, the Treaty entails far-reaching and comprehensive provisions, as it prohibits all forms of acquisition, use and possession of nuclear weapons. The entry into force of the TPNW undoubtedly raises questions of what impact it will have. To evaluate the new Treaty’s impact in terms of its substance, one must first examine already established international law and the legality of acquiring, using and possessing nuclear weapons. Pertaining to the subject of acquisition, it is mainly regulated by the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), which prohibits non-nuclear-weapon State Parties to acquire nuclear weapons. In the analysis of the NPT and its regulation of the acquisition of nuclear weapons it is found that there are some ambiguities in its text and that it does not prohibit proliferation in all instances. Hence, the NPT does not provide a general and absolute prohibition of the acquisition of nuclear weapons. In analysing the legality of the use of nuclear weapons, the areas of jus ad bellum, international humanitarian law, the right to life under human rights law and international environmental law have been considered. By this examination, it is found that international humanitarian law is applicable in most scenarios where there is a risk for use of nuclear weapons. This area of international law considerably limits the possibilities of lawfully using nuclear weapons. With that said, there is no general and absolute prohibition on this subject either. In examining the possession of nuclear weapons, it is found that it is fairly unregulated in international law beyond the new Treaty. However, the most central legal instrument relating to this subject is the NPT. The NPT implicitly prohibits possession of nuclear weapons for the non-nuclear-weapon State Parties, as they are prohibited to acquire such weapons. Furthermore, the NPT entails obligations relating to disarmament, which are concluded to not be fulfilled at this moment. 1 Through this analysis of current international law beyond the new Treaty, it is possible to conclude that there are several legal instruments already applicable to nuclear weapons. There are, however, no general and absolute prohibitions on acquisition, use or possession of nuclear weapons. The new TPNW could thus be of significant impact, as it has the potential of ‘filling in several gaps’ of already established law. Nevertheless, to fully evaluate the new Treaty’s impact, one must also consider its legal effect in terms of creating legally binding obligations, and for what states. As only 54 states have ratified the treaty, it could be concluded that the TPNW has a limited legal effect. There is, however, room to argue that the TPNW also entails obligations for Signatory States. Furthermore, the TPNW could affect nuclear policy and laws regulating the weapons in the future. It can thus be concluded that the impact of the TPNW, despite a limited amount of State Parties, is not insignificant. It is deemed likely that more states will ratify the Treaty, and that it has the potential to create change beyond the legal sphere, in world politics. It also contributes to the discourse focusing on the devastating humanitarian consequences of nuclear weapons and signifies that the only way to prevent the use of nuclear weapons is to eliminate them.