The status of the TPNW
As of July 2024, the Treaty on the Prohibition of Nuclear Weapons (TPNW) has 70 states parties while 27 further states have signed but not yet ratified. This means that a total of 97 states (or 49.2% of all states) have accepted binding obligations in international law under the TPNW. Only 2 more signatures or accessions are needed to pass the 50% mark of the 197 states that can adhere to the treaties in the legal architecture for weapons of mass destruction (WMD).
A total of 100 states are neither party or signatory to the TPNW. On the basis of their most recent voting record on the TPNW in the UN General Assembly, the Nuclear Weapons Ban Monitor identifies 40 of these 100 nonparties as ‘other supporters’. The overall number of TPNW supportive states is thus 137 (or 69.5%), while 43 states are opposed, and 17 states are undecided.
Although signature and ratification is always possible under the TPNW, non-signatory states are especially encouraged to accede to the Treaty. This one-step process is the fastest way to become a state party to the Treaty and join the growing ranks of those who totally reject these weapons of mass murder.
The criteria for the Ban Monitor’s categorisation of states by their position on the TPNW are explained in the table below. For details about individual states, see the state profiles on this website.
Regional distribution of support
Breaking down all states’ positions on the TPNW by region, the figure below shows that support for the TPNW is high in all regions of the world apart from Europe. Looking closer at the distribution of support within each region in the maps further down, it is also clear that it is largely a minority consisting of nuclear-armed states and umbrella states that stand in the way of progress towards universalisation of the TPNW and agreement on nuclear disarmament, while continuing their nuclear weapons-based defence postures that expose all states to unacceptable risk. All but three of the total of forty-three states opposed to the TPNW in 2023 were nuclear-armed states or current or prospective umbrella states, and most were European umbrella states.
Regional maps with distribution of support
Speed of adherence across WMD treaties
With only one new accession (Sri Lanka), the TPNW’s speed of adherence was significantly slower in 2023 than in previous years. This can be explained, in part, by the fact that several signatory states that are working on their ratification process experience administrative challenges, parliamentary backlogs, or political turmoil. At exactly six years after it opened for signature on 20 September 2017, the TPNW had 69 ratifications and accessions. Over the same period of time following opening for signature, the Biological Weapons Convention (BWC) had obtained 74 ratifications and accessions, the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) 78, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) 92, and the Chemical Weapons Convention (CWC) 121 ratifications and accessions.
The figure below shows the speed of ratification and accession of the TPNW relative to the other treaties in the legal architecture for WMD. As it shows, the TPNW fell behind the other treaties at approximately three-and-a-half years after opening for signature but then picked up more speed again after the COVID-19 pandemic before slowing down in 2023. It is clear however, that the TPNW until now at least has followed largely the same trajectory as the NPT and the BWC. The trajectories of the NPT and the BWC serve as a reminder that it took several years also for those treaties to accrue the authority that they have today.
Looking at the number of states parties and signatories combined, as illustrated in the figures below, it is also clear that the TPNW at present is not much behind the NPT at the equivalent point in time. The TPNW allows signature at any time, while the other four WMD treaties only allow accession after entry into force. At six years after entry into force, the NPT had a total of 101 states parties and signatories that had not yet ratified, while the TPNW had 97.
Level of adherence across WMD treaties
In building upon and contributing to the other multilateral WMD treaties, the TPNW has the potential to reinforce the legitimacy of the legal WMD architecture as a whole. This is exemplified by Sri Lanka, which in 2023 adhered to both the CTBT and the TPNW.
The objective must be universal adherence to all of the components in this architecture, meaning that all states should be party to each and every one of them. The figure above therefore highlights all gaps in adherence as of 31 December 2023 among the 197 states that may adhere to the WMD treaties. Where a state is not yet a state party to any of these five treaties, this is noted in its respective state profile on this website along with a recommendation for urgent adherence.
In 2023, the CTBT gained two new states parties (Solomon Islands and Sri Lanka) and one signatory (Somalia), while Russia regrettably withdrew its ratification. The BWC gained one new state party (South Sudan). As mentioned above, the TPNW gained one new state party (Sri Lanka) and two signatories (Bahamas and Djibouti). For the CWC, the latest development was Palestine’s accession in 2018. Palestine was also the most recent country to adhere to the NPT, in 2015.
The most ratified WMD treaty is the CWC, to which only four states are not yet party. One of the four have signed, and three are outliers. The NPT has five outliers, the BWC had four signatories and eight outliers at the end of 2023, and the CTBT 10 signatories and 10 outliers. As discussed above, as of the end of 2023, a total of 100 states were not yet states parties or at least signatories to the TPNW, the youngest treaty in the legal WMD architecture.