5. NATO and the TPNW: Legal Issues
For a NATO member, joining the TPNW would pose considerable political problems for its membership of the Alliance, as it would challenge the political obligations of the latter. Such an act would likely be seen as tantamount, in Matthew Harries’ view, to a denuclearization of extended deterrence, entailing reliance only on a conventional umbrella rather than a nuclear one.94 Relying on a conventional umbrella may not unite the Allies as does the nuclear umbrella, as nuclear weapons have provided a powerful symbolic value to the Alliance – more so than their actual use. In other words, for the foreseeable future, practical regional political difficulties with the TPNW are likely to trump perceived legal ones.
Even so, legal complications of the TPNW for military alliances, as well as its shortcomings as perceived by its opponents, have been the subject of much discussion and examination95 – including by government inquiries such as those of Sweden, Norway, France and Switzerland.96 Some of those inquiries have drawn rebuttals, several quite detailed, such as by the Norwegian Academy of International Law. Comments on criticisms of the TPNW will be discussed in four specific respects: the TPNW’s relationship with the NPT; safeguards for non-proliferation verification; verification of nuclear disarmament; and military assistance and cooperation.97
The TPNW’s relationship with the NPT
As no NATO members have signed or ratified the TPNW, its prohibitions and obligations do not in a legal sense apply to them. But there has been particular questioning about the language of Article 18 of the TPNW, and its description of the relationship between the prohibition treaty and other agreements.98 The suggestion that Article 18 might enable parties to the TPNW to choose to forgo their obligations under other treaties, including the NPT, does not stand up to close scrutiny. It overlooks existing tenets of international law, including Article 30 of the Vienna Convention on the Law of Treaties, governing successive agreements dealing with the same subject matter, and pacta sunt servanda – i.e. every treaty in force is binding on the parties to it. It also overlooks the fact that, as a practical matter, the obligations undertaken by states parties to the TPNW are similar to – and reinforce – the obligations set out in the NPT itself. Criticism directed, for example, at the new treaty’s failure to permit reservations, and at its inclusion of a withdrawal clause, fail to appreciate that these provisions essentially follow the approach adopted by the NPT.99
In addition, in its 1996 advisory opinion, the ICJ has established that: ‘A weapon that is already unlawful per se, whether by treaty or custom, does not become lawful by reason of its being used for a legitimate purpose under the Charter.’100 While the advisory opinion does not classify nuclear weapons as unlawful per se, one current concern nuclear weapon states may have is the possibility of a prohibition on nuclear weapons becoming customary in international law. Other than conventional treaty law, international legal norms are also composed of customary international law, a body of rules that find their source from the ‘evidence of a general practice accepted as law’,101 and that must be respected by all subjects of international law. The US, the UK and France issued a joint statement immediately following the adoption of the TPNW, rejecting ‘any claim that this treaty reflects or in any way contributes to the development of customary international law’.102 This move, along with their persistent rejection of the TPNW, can have two implications:
- Preventing the actual development of a customary international law prohibiting nuclear weapons;103 and
- Treating them as ‘persistent objectors’, which may render a customary prohibition on nuclear weapons inapplicable to these nuclear weapon states.104
Safeguards for non-proliferation verification
Efforts in the TPNW negotiations to promote stronger safeguards (i.e. the IAEA’s Additional Protocol105) unfortunately fell short, just as they have for many years in the NPT. Indeed, it will be a challenge for the NPT Review Conference to achieve something that its predecessors have so far failed to do – to strengthen the NPT by requiring parties to go beyond the Article III baseline obligation of negotiating and concluding comprehensive safeguards agreements with the IAEA. The TPNW does, however, specifically adopt the NPT’s current safeguards,106 and exceeds the NPT by requiring – as a legal obligation under Article 3.1 of the prohibition treaty – that those of its parties with an IAEA Additional Protocol retain that protocol in place as their minimum baseline.107
Verification of nuclear disarmament
In the TPNW, verification of disarmament efforts is confined, for the time being, to a limited outline. In their paper for the Norwegian Academy of International Law, Gro Nystuen et al. note that negotiating detailed verification provisions without the participation of the nuclear weapon states was ‘deemed impractical’:108 the architects of the prohibition treaty consciously deferred the essential aspect of how the elimination of nuclear weapon programmes should be verified, organized and resourced. Those details were left to development at the point at which Article 4 of the TPNW would be invoked on the accession to the prohibition treaty of a nuclear weapon-possessing state, or one that has declared that it has disarmed prior to acceding. TPNW parties are required under paragraph 6 of Article 4 to designate a competent international authority or authorities to ‘negotiate and verify the irreversible elimination of nuclear weapon programmes, including the elimination or irreversible conversion of all nuclear weapons-related facilities’.109
As mentioned earlier, the Netherlands – the sole NATO member present throughout the negotiation of the treaty – based its vote against the adoption of the TPNW on the grounds that the new treaty was ‘not verifiable’.110 It is too early to predict the shape of the necessary verification mechanisms under a prohibition regime that has still to convene its first formal meeting of states parties (MSP)111 to determine how best to implement the Treaty. But in the meantime, the development of robust mechanisms for the verification of nuclear disarmament in TPNW MSPs, as in NPT review cycles, remains to be tested.
Military assistance and cooperation
Becoming party to the TPNW would not curtail military cooperation among non-nuclear weapon NATO members, their nuclear weapon partners, or NATO’s PfP partners, except in one specific respect. Article 1.1 (g) prohibits any stationing, installation or deployment of any nuclear weapons or other nuclear explosive devices in each state party’s territory or at any place under its jurisdiction or control. This reflects the situation that arises for the five NATO members that currently host US nuclear weapons. But these are matters of national choice, not NATO obligation. For instance, by analogy to other arms control prohibitions, a number of NATO members that possessed weapon systems prohibited by the Anti-Personnel Mine Ban Convention (APMBC) and the Convention on Cluster Munitions (CCM) were able to become party to those conventions once they met the required conditions of the conventions – i.e. destruction of the prohibited weapons within stipulated timelines. They were able to do without compromising their status in NATO vis-à-vis NATO non-parties to those agreements. For instance, the CCM allows (in Article 21) for military cooperation and operations to continue with non-party allies despite the risk that CCM parties may, due to their role in such operations, be associated with the use, stockpiling and transfer of cluster munitions. However, there is no equivalent in the TPNW to Article 21 of the CCM.112 Parties to the TPNW could participate in joint military operations with a nuclear weapon state without contravening the treaty, provided there is no nexus between a particular task and an activity prohibited by the TPNW such as the stationing one just mentioned.113
Observing TPNW meetings, however, could be a positive step. Article 8.5 of the TPNW provides that: ‘States not party to this Treaty, as well as the relevant entities of the United Nations system, other relevant international organizations or institutions, regional organizations, the International Committee of the Red Cross, the International Federation of Red Cross and Red Crescent Societies and relevant non-governmental organizations, shall be invited to attend the meetings of States Parties and the review conferences as observers.’ Switzerland, for one, is aware of this opportunity.114 Participation in treaty meetings by non-parties as observers is not uncommon in international law. For example, Israel observed the NPT Review Conference in 2015: seeking observer status in such circumstances does not create any commitment in terms of signature or ratification by a non-party. But availing itself of the opportunity to monitor directly meetings of states parties implies a state’s serious interest in those proceedings.
94 Harries, M. (2017), ‘The ban treaty and the future of US extended nuclear deterrence arrangements’.
95 See for example Hajnoczi, T. (2020), ‘The Relationship between the NPT and the TPNW’, Journal for Peace and Nuclear Disarmament, doi: 10.1080/25751654.2020.1738815 (accessed 2 Apr. 2020).
96 For the report of the Swedish inquiry (including an English translation of the executive summary), see Ministry of Foreign Affairs (2019), Utredning av konsekvenserna av ett svenskt tillträde till konventionen om förbud mot kärnvapen. Inquiry into the consequences of a Swedish accession to the Treaty on the Prohibition of Nuclear Weapons, https://www.regeringen.se/48f047/contentassets/55e89d0a4d8c4768a0cab
f4c3314aab3/rapport_l-e_lundin_webb.pdf. For the Norwegian report, see Ministry of Foreign Affairs (2018), ‘Review of the consequences for Norway of ratifying the Treaty on the Prohibition of Nuclear Weapons’. For the Swiss report, see Federal Department of Foreign Affairs (2018), Report of the Working Group to analyse the Treaty on the Prohibition of Nuclear Weapons.
97 In addition to the criticisms set forth in this paper, critics of the TPNW have also noted the need for greater clarity on the treaty’s scope. This aspect is of particular importance in the context of the EU, in light of the European Council Regulation No. 428/2009 (of 5 May 2009, 2017 consolidated version), which provides for the exports, transfers, brokering and transit of dual-use items, including those that can be used for ‘assisting in any way the manufacture of nuclear weapons or other nuclear explosive devices’. The interpretation of this provision, binding on all EU member states, may vary from one state to another in the event that EU member states become party to the TPNW (e.g. Austria) once the treaty enters into force, in light of its prohibition of assistance. A lack of clarity may greatly affect the ‘harmonious’ interpretation of EU law across all member states of the Union. For a discussion on the assistance aspect, see Casey-Maslen, S. (2018), ‘The Nuclear Weapons Prohibition Treaty: Interpreting the Ban on Assisting and Encouraging’, Arms Control Today, October 2018, https://www.armscontrol.org/act/2018-10/features/nuclear-weapons-prohibition-treaty-interpreting-ban-assisting-encouraging (accessed 24 Oct. 2019).
98 Article 18, TPNW covers the treaty’s relationship with other agreements: ‘The implementation of this Treaty shall not prejudice obligations undertaken by States Parties with regard to existing international agreements, to which they are party, where those obligations are consistent with the Treaty.’
99 New Zealand (2017), ‘Nuclear weapons Statement by New Zealand, Delivered by H.E Dell Higgie, Ambassador for Disarmament’, 13 October 2017, https://s3.amazonaws.com/unoda-web/wp-content/uploads/2018/11/statement-by-new-zealand-72-nw.pdf (accessed 16 Oct. 2019).
100 International Court of Justice (1996), Legality of the Threat or Use of Nuclear Weapons, para. 39.
101 Article 38(1)(b) of the Statute of the International Court of Justice (Annex to the UN Charter) defines an international custom as ‘evidence of a general practice accepted as law’.
102 Permanent mission on France to the United Nations in New York (2017), ‘Joint Press Statement from the Permanent Representatives to the United Nations of the United States, United Kingdom, and France following the adoption of a treaty banning nuclear weapons’, 7 July 2017, https://onu.delegfrance.org/Adoption-of-a-treaty-banning-nuclear-weapons (accessed 16 Mar. 2020). These states have also indicated individually their objection to any formation of customary law from the beginning. For example, see France, Statement to the United Nations General Assembly 72 First Committee, 14 October 2017, https://undocs.org/A/C.1/72/PV.16 (accessed 23 Mar. 2020).
103 Based on the definition of international customs provided by Article 38(1)(b) of the Statute of the ICJ, a norm requires two elements to obtain the status of ‘customary’ international law: (1) general state practice, and (2) the belief that the norm in question is of customary nature and is binding upon them. With an overwhelming support within the UN General Assembly for the launch of the negotiations leading to the adoption of the TPNW, as well as the growing number of signatory states, the practice of prohibiting nuclear weapons could therefore be argued as constituting a ‘general practice accepted as law’. However, the definition provided by the ICJ Statute requires ‘evidence’ of state practice and acceptance – thus requiring positive actions: in other words, states (in particular those of most relevance to the norm in question, i.e. nuclear weapon states and other nuclear possessors) need to proactively accept this norm. The fact that China, India and Pakistan abstained on the adoption of Resolution 71/258 to mandate the negotiation of the TPNW may be enough to establish that the ‘general’ state practice element is missing for the complete formation of a customary norm. The active objection by the US, the UK and France of this norm as customary adds further evidence that a prohibition of nuclear weapons does not constitute, at present, a customary international law.
104 In the event of the prohibition of nuclear weapons becoming customary international law, this norm will be applicable and must be enforced by all subjects of international law – with the exception of persistent objectors. These are subjects of international law who have persistently objected, from the formation and development stages of the customary norm in question, against the norm in question. This notion has been set by the ICJ, in its 1951 Fisheries (United Kingdom v Norway) case. For a discussion on persistent objectors, see Dumberry, P. (2010), ‘Incoherent and Ineffective: The Concept of Persistent Objector Revisited’, International and Comparative Law Quarterly, 59(3), pp. 779–802, doi: 10.1017/S0020589310000308 (accessed 16 Mar. 2020).
105 There is an ongoing debate as to whether the safeguards regime in the TPNW has a lower standard of safeguards level than the standard set by the IAEA Additional Protocol, or whether it is actually of a higher standard than for a new state joining the NPT. For more information on the Additional Protocol, see IAEA (1998–2020), ‘Additional Protocol’, https://www.iaea.org/topics/additional-protocol (accessed 20 May 2020).
106 International Atomic Energy Agency (IAEA) (1971, reprinted 1972), The Structure and Content of Agreements between the Agency and States Required in Connection with the Treaty on the Non-Proliferation of Nuclear Weapons, INFCIRC/153 (Corrected), Austria: IAEA, https://www.iaea.org/sites/default/files/publications/documents/infcircs/1972/infcirc153.pdf (accessed 29 Oct. 2019).
107 Nystuen, G., Egeland, K., Hugo, T. G. (2018), The TPNW: Setting the record straight, Norwegian Academy of International Law, p. 11, http://intlaw.no/wp-content/uploads/2018/10/TPNW-Setting-the-record-straight-Oct-2018-WEB.pdf (accessed 16 Oct. 2019).
108 Ibid., p. 15.
109 Article 4, TPNW.
110 The Netherlands (2017), ‘Explanation of vote of the Netherlands on text of Nuclear Ban Treaty’.
111 Article 8, TPNW.
112 As New Zealand noted pointed in 2017, the possibility of making reservations and of withdrawal follows the NPT’s approach. See New Zealand (2017), ‘Nuclear Weapons Statement by New Zealand, Delivered by H.E. Dell Higgie, Ambassador for Disarmament’. See also: Harries, M. (2017), ‘The ban treaty and the future of US extended nuclear deterrence arrangements’.
113 Human Rights Program at Harvard Law School (2018), Nuclear Umbrella Arrangements and the Treaty on the Prohibition of Nuclear Weapons, p. 5.
114 Federal Department of Foreign Affairs (2018), Report of the Working Group to analyse the Treaty on the Prohibition of Nuclear Weapons.