Does the TPNW Contradict or Undermine the NPT?

Photo credit: UN Photo / Paulo Filgueiras

The Treaty on the Prohibition of Nuclear Weapons (TPNW) unnecessarily has become a bitter bone of contention between the non-nuclear-weapon States (NNWS) supporting this treaty and most of the nuclear-armed States and US allies in defence arrangements underpinned by US nuclear weapons. The opponents of the TPNW have raised a number of concerns and shortcomings relating to the TPNW. This short paper responds to some of these.

Critics claim that the TPNW does not:

1. define a nuclear weapon: This is correct it does not – but neither does the non-proliferation treaty (NPT) nor four of the five nuclear-weapon zone (NWFZ) treaties – only the Treaty of Tlateloloco has a definition (article 5);
2. constitute an “effective measure” for nuclear disarmament under the nuclear Non-Proliferation Treaty (NPT) (article VI): The TPNW is an “effective measure” as called for in NPT Article VI on nuclear disarmament, in parallel with the 1996 Comprehensive Nuclear-Test-Ban Treaty (CTBT), the bilateral USSR/Russia-US treaties such as 2010 New START and the 1987 Intermediate-Nuclear Forces Treaty (INF) even though these were concluded for national security not NPT reasons; and the five nuclear-weapon-free zone (NWFZ) treaties operational in Latin America and the Caribbean, South Pacific, Southeast Asia, Africa and Central Asia; the NPT is not a self-implementing treaty, it requires enabling actions, for example, safeguards agreements by NNWS with the International Atomic Energy Agency (IAEA) to verify non-proliferation commitments under Articles II and III of the NPT; NWFZ treaties are required to implement Article VII, while nuclear cooperation agreements are needed to implement Article IV of the NPT on peaceful uses of nuclear energy; 
3. include the latest IAEA safeguards (Additional Protocol): To be precise, Article 3 of the TPNW stipulates that each NNWS party “shall, at a minimum, maintain its [IAEA] safeguards obligations in force at the time of entry into force of this Treaty, without prejudice to any additional relevant instruments that it may adopt in the future”; while it is indeed unfortunate that the IAEA’s Board of Governors has been unable to agree to make the 1997 Model Additional Protocol (AP)(INFCIRC/540) an essential component of the IAEA NPT comprehensive safeguards agreement (INFCIRC/153) for NPT NNWS, and the IAEA General Conference in its annual safeguards resolution has said that “it is the sovereign decision of any State to conclude an additional protocol”; the TPNW requires adhering NNWS to maintain, as a minimum, their existing safeguards agreements and provides for further strengthened safeguards, thus for the 80% of NPT NNWS with APs in force, the TPNW secures the current de facto standard of non-proliferation verification, which is higher than the one stipulated by the NPT; and
4. include verification of nuclear disarmament: This is correct, but neither the NPT nor NWFZ treaties include the technical details of verification. This is left to the “Agency’s [IAEA] safeguards system” in reality. The IAEA collaboratively with its Member States during 1970-1971 drew up (INFCIRC/153) comprehensive safeguards after the entry into force in 1970 of the NPT and the Additional Protocol (INFCIRC/540) during 1993-1997; TPNW/IAEA States, at the first meeting of States Parties to be convened within one year of the entry into force of the TPNW, should invite the IAEA to set up a technical working group to develop verification approaches and to this end sponsor a resolution at the 2021 IAEA General Conference; and unlike the 1972 Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction (BTWC) that has acquired customary international law status and has no provisions for verification, the TPNW does in fact stipulate an approach to verification.

Other criticisms, for example, include that:

1. the TPNW is inconsistent as it allows for States with nuclear weapons to adhere to it and it also allows States to join that had nuclear weapons but have disarmed: It is instructive to recall that the Chemical Weapons Convention (CWC) allows both declared chemical weapon possessor States as well as those that have previously destroyed their CW stocks to adhere to the CWC; hence the TPNW follows similar logic, States with nuclear weapons can adhere to the TPNW and then proceed to verifiably destroy them under auspices of a competent international authority to be designated by States parties;
2. the TPNW “demonstrates that there is no legal norm on non-possession of nuclear weapons”: One of the purposes of the TPNW is to establish a legal norm against the possession of nuclear weapons, much along the lines of the BTWC and CWC outlawing biological and chemical weapons respectively; 
3. the TPNW will establish a “competitor regime to the NPT” and may entice “defections from the NPT”: The Treaty of Tlatelolco was the first to “prohibit” nuclear weapons in its zone of application and the subsequent four NWFZ treaties renounce nuclear weapons, but none are regarded as competitors or alternatives to the NPT; rather they are considered as complementary; and it is spectacularly illogical to suggest that a TPNW State party could “defect” from the NPT to “shirk” its non-proliferation obligations because as already noted above the TPNW itself requires each State party to “at a minimum, maintain its International Atomic Energy Agency safeguards obligations in force at the time of entry into force of this Treaty, without prejudice to any additional relevant instruments that it may adopt in the future” (article 3);
4. the TPNW would “delegitimize extended deterrence alliance relationships” and thus incentivize alliance NNWS to develop indigenous nuclear weapon programmes: Such a claim calls into question the integrity and commitment of alliance NNWS to the NPT and suggests that their non-proliferation credentials may be suspect as their fealty to the NPT is only because of reliance on extended nuclear deterrence thus a case of “having one’s cake and eating it too”, i.e. to benefit from nuclear weapons, including in cases where such weapons are stationed on their territory, without actual possession, and also to preach non-proliferation to other NNWS, and thus result in effectively undermining trust in the NPT. 

To conclude it is abundantly clear that the TPNW shall create a prohibition of nuclear weapons, under customary international law, when it enters into force and more of the 122 States that voted for it complete their ratification procedures, and as such establish a jus cogens rule creating an erga omnes not only for all NPT States parties but for other nuclear-armed States as well.