The obligation to adopt national implementation measures

Very few states parties have adopted a specific law to give effect to their obligations under the TPNW. Many states parties, especially those whose domestic legal order is monist in nature, have noted that ratified treaties become part of the law of the land. Others note that their existing criminal law effectively covers the prohibitions in Article 1 of the TPNW. Nonetheless, each state party is encouraged to develop detailed legislation either specific to the TPNW or which includes its prohibitions in a broader law. In particular, new national legislation should be adopted by each state party to the TPNW that does not yet have in place laws to criminalise the acts prohibited by the Treaty and, where necessary, to implement its positive obligations.

Most non-nuclear-armed states are already today implementing most of the core prohibitions of the TPNW. As illustrated by the table below, this is because they pursue nuclear-weapon-free defence postures and are states parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), the Comprehensive Nuclear-Test-Ban Treaty (CTBT), and the nuclear-weapon-free zone (NWFZ) treaties, and because they have brought into force safeguards agreements with the International Atomic Energy Agency (IAEA). Typically, therefore, they already have in place appropriate national measures, including legislation that addresses all or at least some of the core obligations under the TPNW. Accordingly, the adoption of new national legislation to implement the TPNW may not be necessary.

Crucially, however, all states parties to the TPNW have to establish whether their existing national laws would make it illegal for a national or any other person under their jurisdiction or control to develop, produce, possess, control, transfer, or use nuclear weapons, or to assist any other person or entity to do so, and whether they could prosecute them. If the answer is a clear yes, they have the required national legislation. In most states, engaging in conduct prohibited by the TPNW would ordinarily be a crime even if it is not specifically outlawed, because the handling of dangerous substances (which would encompass nuclear material) is prohibited.

To the knowledge of the Nuclear Weapons Ban Monitor, only states parties Ireland and Niue have adopted national legislation specifically to implement the TPNW. Ireland adopted its Prohibition of Nuclear Weapons Act in 2019. The list of offences in Section 2 of the Act reflects Article 1(1) of the TPNW and an offence may be committed by both an individual and a company. Niue adopted its Prohibition of Nuclear Weapons Act in 2021. The Act is explicitly aimed at giving effect to the TPNW.

See the 2023 edition of the Nuclear Weapons Ban Monitor for information on states parties that when adhering to the TPNW had in place comprehensive existing legislation that addresses some or all of the obligations under the Treaty, as well as states parties where national law is under development.