3. NATO and the NPT
Two aspects related to the possession of and reliance on nuclear weapons have come to the fore in the current NPT review cycle. The first arises in connection with the serious state of international security, while the second, involving the doctrine of deterrence, has been brought into close scrutiny by the emergence of the TPNW. They are examined here under these propositions:
- Global security environment: To what extent does the current global security environment constitute a valid justification for retaining nuclear weapons (in current numbers as well as modernizing them)?
- Extended deterrence: On what premise do those non-nuclear weapon states that are members of nuclear alliances base their reliance on a class of weapon of mass destruction that they renounced when they joined the NPT?
Global security environment
While all nuclear and non-nuclear states parties to the NPT share legal obligations and a mutual commitment to non-proliferation, they have long contested the weight of attention that should be placed on implementation of the nuclear disarmament obligation. This dynamic – a feature of the review conferences – is currently reflected in the stance of nuclear weapon states and their allies32 that today’s tense international environment is not conducive to further progress on nuclear disarmament. For instance, a 2017 NATO communiqué emphasized:
… progress on arms control and disarmament must take into account the prevailing international security environment. We regret that the conditions for achieving disarmament are not favourable today.33
With North Korea and, to a lesser extent, Iran in mind, proponents of this view often maintain that the focus should instead be on actual or suspected instances of nuclear proliferation.34
Prevention of nuclear weapon proliferation is a matter of universal interest. In the NPT context, however, two related matters arise. Does actual or suspected proliferation justify the continued retention of existing nuclear arsenals of NPT parties until global security is somehow restored and reductions are resumed? And until that point is reached (as determined by whom and how?), can non-nuclear weapon parties to the NPT legitimately shelter under the nuclear umbrella or ‘extended deterrence’ provided by their military allies? For many non-nuclear weapon states, however, there is a prior question. Do existing nuclear arsenals undermine35 rather than enhance global security – another perennial point of contention in NPT review conferences?
In other words, the likelihood that most non-nuclear weapon states would accept that global security equilibrium is essential for nuclear disarmament is low. Equally, it is unlikely that nuclear weapon states would accept that the pursuit of nuclear disarmament leads to ameliorating the security environment. NPT parties need to acknowledge that this divergence, far from reducing existing tensions in the NPT process, is in reality exacerbating international tensions.
The significance of the global security environment to the implementation of the NPT stems from several provisions of the treaty. The first of these is the penultimate paragraph of the preamble, which records the ‘desire’ of the negotiators to:
… further the easing of international tension and the strengthening of trust between States in order to facilitate the cessation of the manufacture of nuclear weapons, the liquidation of all their existing stockpiles, and the elimination from national arsenals of nuclear weapons and the means of their delivery pursuant to a Treaty on general and complete disarmament under strict and effective international control.36
The second provision of relevance is Article VI, a binding obligation to ‘pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control’.37
Traditionally, a treaty’s preamble is not cast in binding legal terms. Rather, it reflects the purposes and considerations that motivated the parties to conclude the treaty. Its main use is to provide an interpretative tool when a specific legal obligation comes under scrutiny – in this instance, Article VI.38 The preamble reflects the expectation of the negotiators that an easing of tension and a building of trust would progressively facilitate the halting of production, the liquidation of stockpiles and the elimination of nuclear weapons from national arsenals. The key word here is ‘facilitate’. The cessation of manufacture, destruction of stockpiles and elimination of nuclear weapons and their means of delivery is not made conditional on the state of global security. Rather, it is perceived that this process will be easier in a climate of trust and reduced tension. As the preamble also envisages, such a process would serve the declared intention of the parties of achieving ‘at the earliest possible date the cessation of the nuclear arms race’ and the undertaking of ‘effective measures in the direction of nuclear disarmament’.39
The preamble to the NPT reflects the expectation of the negotiators that an easing of tension and a building of trust would progressively facilitate the halting of production, the liquidation of stockpiles and the elimination of nuclear weapons from national arsenals. The key word here is ‘facilitate’.
Reference must also be made to the phrase that is common to both the NPT preamble and Article VI: the concept of a future treaty on ‘general and complete disarmament under strict and effective international control’.40 This ambition has been on the UN General Assembly’s agenda since 1959,41 and was declared by consensus at the General Assembly’s first Special Session on Disarmament, in 1978, to be the UN’s ‘ultimate goal’42 in this field.43 The notion of general and complete disarmament recognizes that nuclear disarmament ‘will not occur or be sustainable in isolation of other considerations of international peace and security, including the status of conventional force holdings’, and that it will proceed only under strict and effective control – i.e. with international verification and safeguards.44
General and complete disarmament can be likened to the comprehensive approach pursued by UN Secretary-General António Guterres’ Disarmament Agenda,45 which ‘associates disarmament and arms control as vital to the future of international peace and security and frames the relationship between disarmament and security as mutually reinforcing and interdependent’.46 In the case of the NPT, as just explained, security is not a prerequisite for disarmament but facilitates it. It is in this sense that NATO’s recognition of the need to create the conditions for a world without nuclear weapons should be seen.
Indeed, among NATO members, the need for shaping a constructive discussion on global security in the context of nuclear disarmament has already been recognized in a substantive manner by the US. In 2018, US Assistant Secretary (of State) Dr Chris Ford initiated a working group – Creating an Environment for Nuclear Disarmament (CEND) – on ways to make the security environment more conducive to further progress towards nuclear disarmament.47 The inaugural meeting of the working group, attended by 42 states at the invitation of the US, was held in Washington in July 2019. Nuclear-armed states from within and outside the NPT, and non-nuclear weapon states including some NATO allies and representatives of states supporting the TPNW, participated.
Three subgroups were formed, with each one discussing these three topics:
- Measures to modify the security environment to reduce incentives for states to retain, acquire, or increase their holdings of nuclear weapons;
- Institutions and processes nuclear weapon states and non-nuclear weapon states can put in place to bolster non-proliferation efforts and build confidence in nuclear disarmament; and
- Interim measures to reduce the likelihood of war among states that possess nuclear weapons.
The first meeting of the CEND working group took place in a constructive atmosphere, prompting the idea of expanding the number of country and civil society participants.48 The US, however, in its original invitation did encourage invitees to consult others in their region to identify local or other security conditions affecting disarmament prospects. Leaving aside the prospects for expanding CEND participation, its establishment represents at least a willingness to provide a forum for constructive dialogue. A further, slightly smaller, meeting was held in London in November 2019. A third meeting was anticipated for early 2020, but, like the Review Conference, has been postponed because of COVID-19.49 As in the NPT Review Conference, it is up to states as to how they fashion such tools for progress.
Extended nuclear deterrence
The doctrine of nuclear deterrence is employed by nuclear weapon states as a means of dissuading an adversary from attacking them or, via ‘extended deterrence’, their alliance partners, out of fear of retaliatory strikes using nuclear weapons.50 Deterring aggression is a long-standing tenet of human survival – one that has been given new meaning in the nuclear age. This is because the inherent threat of use of nuclear weapons in retaliation for an act of aggression relies on inducing ‘caution in others by threats of pain’, the failure of which would result in catastrophic consequences.51
Indeed, the deep concern about the ‘catastrophic humanitarian consequences of any use of nuclear weapons’ that was shared by all NPT states parties in the agreed outcome to the 2010 Review Conference recalls the stark wording in the preamble to the NPT: ‘the devastation that would be visited upon all mankind by a nuclear war’.52 Given the immensity of the consequences of nuclear war, the risk of failing to avert such a calamity evokes the Cold War label ‘mutually assured destruction’, or MAD – an acronym not coined in jest.53
The dependence of some non-nuclear weapon states on nuclear alliances is in fact often seen by those non-nuclear weapon states that are without such alliances or binding assurances for their own security as inconsistent with the spirit of the NPT’s non-proliferation pillar, as well as with the nuclear disarmament one. That is, as long as nuclear weapons are claimed to provide security for some states, others may want to acquire them for their own security. Another angle, as noted by former Canadian ambassador Paul Meyer, is that the ‘dissenting minority’ of non-nuclear weapon states are in effect obliged, as nuclear alliance states:
… to affirm that nuclear weapons have security benefits, which sits uneasily with traditional support for nuclear disarmament under the NPT including the 2000 NPT Review Conference’s “unequivocal undertaking by the nuclear weapon states to accomplish the total elimination of their nuclear arsenals.”54
For nuclear weapon states, however, and for their military allies, reliance on nuclear arms to deter attacks on any of them carries an unshakeable logic despite – indeed because of – the high stakes involved. Nuclear weapons are seen as having helped avert major, region-wide conflicts for over 70 years.55 It is the existence of nuclear weapons, by this logic, that prevents any humanitarian catastrophe. That is not to say that these states relish the prospect of any use of nuclear weapons.56 Indeed, they claim principled leadership in their strenuous efforts taken during the life of the NPT to date to discourage, curtail, prevent or obviate proliferation by other states. In this regard, it is generally accepted that the fact that the number of countries in possession of a nuclear arsenal remains in single figures is a major success of international vigilance and of the treaty itself. Commenting in 2017 on the ‘profound link between non-proliferation and extended nuclear deterrence’, former NATO deputy secretary-general Rose Gottemoeller asserted that the US nuclear umbrella had in essence made the NPT possible:57 ‘It gave U.S. allies and partners in Europe and Asia the confidence to put aside their own nuclear weapons research and to become non-nuclear weapon states under the NPT.’58 This should, however, be considered alongside other factors that may have dissuaded those states from developing their own nuclear weapons programme, including the transfer of knowledge for peaceful uses of nuclear energy.59
The dependence of some non-nuclear weapon states on nuclear alliances is in fact often seen by those non-nuclear weapon states that are without such alliances or binding assurances for their own security as inconsistent with the spirit of the NPT’s non-proliferation pillar, as well as with the nuclear disarmament one.
The doctrine of nuclear deterrence, nonetheless, is the source of constant tension among NPT states parties. The need to deter conflict as much as possible is not contentious. What is at issue, in the view of many non-nuclear weapon states, is the threat of use of nuclear weapons to deter aggression. Deployment of such destructive and inherently indiscriminate armaments is regarded by those states as incompatible with international humanitarian law. Failure of the doctrine of nuclear deterrence, as already noted, could entail a humanitarian tragedy of regional, if not, global consequence, with disproportionate civilian casualties.
NATO: extended deterrence and threat of use
Any legal discussion of nuclear deterrence invites consideration of the use or threat of use of nuclear weapons. In the case of an explicit threat of use, the 1996 advisory opinion of the International Court of Justice (ICJ) on the Legality of the Threat or Use of Nuclear Weapons60 held that it was unlawful to issue threats that would be illegal if carried out in practice. But the court declined to address the matter of whether the use of nuclear weapons would be unlawful when the ‘survival’ of the state using nuclear weapons was in jeopardy – that is, as an act of self-defence.
On the one hand, this could be interpreted as suggesting that, as far as an alliance is concerned, the threat or use of nuclear weapons would not be permissible if carried out on behalf of another state, as the survival of the user would presumably not be in jeopardy.61 On the other, the practice of extended nuclear deterrence could be seen as constituting part of the inherent right of states to undertake collective self-defence, enshrined in Article 51 of the UN Charter.62 The practice of collective self-defence may potentially be lawful only if it respects certain conditions.63 In the same advisory opinion, the ICJ established that the legality of a threat to use force (thus, by extension, the policy of deterrence) is contingent on the legality of the envisaged use of force.64 In other words, the particular use of force envisaged must not be ‘directed against the territorial integrity or political independence of a State, or against the Purposes of the United Nations or whether, in the event that it were intended as a means of defence, it would necessarily violate the principles of necessity and proportionality’.65 Whether the practice of extended deterrence in a given situation is lawful would therefore depend on whether the envisaged use would be lawful under international law, even if the protected state has requested such protection.
Moreover, the ICJ noted that ‘a use of force that is proportionate under the law of self-defence, must, in order to be lawful, also meet the requirements of the law applicable in armed conflict which comprise in particular the principles and rules of humanitarian law’.66 Such use of nuclear weapons would need to respect the customary rules of distinction (between combatants and civilians, and between military objectives and civilian objects), proportionality, and precautions (that such attack would spare civilians and civilian objects). The question of whether use of nuclear weapons would inherently violate jus in bello (international humanitarian law, or the law of armed conflict) is beyond the scope of this paper.67
To anticipate briefly the next chapter of this paper, it has been argued for alliance partners, that passive reliance by a non-nuclear weapon state on the nuclear weapons of a state with which it is allied under extended deterrence would not be inconsistent with the TPNW’s prohibition of threatening to use under Article 1.1 (d). Nor would that provision encompass the mere possession of nuclear weapons: nuclear deterrence is not in and of itself an unlawful threat to use nuclear arms.68 But this point should not be taken to be founded on, or to extend to, any claim that nuclear deterrence may be considered as a legitimate means of obviating use of those arms. Taken to its logical conclusion, the rationalization that the nuclear deterrence doctrine exists in effect to forestall the detonation (and non-proliferation) of nuclear weapons – i.e. that the use of nuclear weapons, for as long as such weapons exist, is confined to preventive purposes, sits uneasily with the objects and purposes of the NPT as outlined earlier. If this point is a defence of the status quo, it sits uncomfortably with the reality that in today’s fractious world the risks of nuclear warfare appear greater than they have been since the depths of the Cold War.69
32 See for example UK Mission to UN in New York and UK Mission to the WTO, UN and Other International Organisations (Geneva) (2018), ‘P5 Joint Statement on the Treaty on the Non-Proliferation of Nuclear Weapons’, 24 October 2018, https://www.gov.uk/government/news/
p5-joint-statement-on-the-treaty-on-the-non-proliferation-of-nuclear-weapons (accessed 22 Oct. 2019).
33 NATO (2017), ‘North Atlantic Council Statement on the Treaty on the Prohibition of Nuclear Weapons’.
34 See for example the US statement to the United Nations General Assembly First Committee, 3 October 2017, https://undocs.org/A/C.1/
72/PV.3 (accessed 11 Oct. 2019).
35 The New Agenda Coalition goes as far as to assert that ‘nuclear weapons ultimately constitute a security risk for all states, including nuclear weapon states, and that nuclear disarmament is as much a security imperative as it is a humanitarian one’: See Working paper submitted by Brazil on behalf of the New Agenda Coalition (Brazil, Egypt, Ireland, Mexico, New Zealand and South Africa) (2019), ‘Taking forward nuclear disarmament’, 26 April 2019, Preparatory Committee for the 2020 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, NPT/CONF.2020/PC.II/WP.13, para. 14, https://undocs.org/pdf?symbol=en/NPT/CONF.2020/PC.III/WP.35 (accessed 11 Oct. 2019).
36 Preamble, NPT.
37 Article VI, NPT.
38 The preambles may be considered as part of the elements contributing to the interpretation of treaties in accordance to articles 31 and 32 of the 1969 Vienna Convention on the Law of Treaties.
39 Preamble, NPT.
40 Ibid; see also Article VI, NPT.
41 United Nations General Assembly (1959), Resolution 1378 (XIV), ‘General and complete disarmament’, 20 November 1959, https://undocs.org/
en/A/RES/1378(XIV) (accessed 11 Oct. 2019).
42 Note also the telling use of ‘ultimate objective’ in step 11 of the 13 practical steps accepted by consensus at the NPT Review Conference in 2000 (and deliberately separated from step 6 – the unequivocal undertaking by the nuclear weapon states to accomplish the total elimination of their nuclear arsenals): this phrase reflects the fundamental desire of NPT states parties to achieve general and complete disarmament as an ‘ultimate objective’ (thus implying a process beforehand), instead of seeing general and complete disarmament as a pre-requisite, sine qua non condition to nuclear disarmament.
43 United Nations General Assembly (1978), A/S-10/2, ‘Final Document of the Tenth Special Session of the General Assembly’, paras. 109 and 111, 28 June 1978, https://s3.amazonaws.com/unoda-web/wp-content/uploads/2017/05/A-S10-4.pdf (accessed 22 Oct. 2019).
44 Rydell, R. (2016), ‘Creating disarmament synergies: The general and complete disarmament multiplier’ in United Nations Office for Disarmament Affairs (2016), UNODA Occasional Papers No. 28, Rethinking General and Complete Disarmament in the Twenty-first Century, New York: United Nations Office for Disarmament Affairs, https://unoda-web.s3-accelerate.amazonaws.com/wp-content/uploads/assets/publications/occasionalpapers/en/op28.pdf (accessed 22 Oct. 2019).
45 United Nations Office for Disarmament Affairs (2018), Securing Our Common Future, An Agenda for Disarmament, New York: United Nations Office for Disarmament Affairs, https://s3.amazonaws.com/unoda-web/wp-content/uploads/2018/06/sg-disarmament-agenda-pubs-page.pdf#view=Fit (accessed 29 Oct. 2019).
46 See Rydell, R. (2019), ‘The Guterres Disarmament Agenda’, Arms Control Today, January/February 2019, https://www.armscontrol.org/act/2019-01/features/guterres-disarmament-agenda (accessed 29 Oct. 2019).
47 Working paper submitted by the United States of America (2019), ‘Operationalizing the Creating an Environment for Nuclear Disarmament (CEND) Initiative’, 26 April 2019, Preparatory Committee for the 2020 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, NPT/CONF.2020/PC.III/WP.43, https://undocs.org/pdf?symbol=en/NPT/CONF.2020/PC.III/WP.43 (accessed 11 Oct. 2019).
48 For commentary on CEND’s work, see Potter, W. C. (2019),’Taking the Pulse at the Inaugural Meeting of the CEND Initiative’, Middlebury Institute of International Studies at Monterey, 15 July 2019, https://www.nonproliferation.org/taking-the-pulse-at-the-inaugural-meeting-of-the-cend-initiative/ (accessed 11 Oct. 2019). See further points: Burford, L., Meier, O., Ritchie, N. (2019), ‘Sidetrack or kickstart? How to respond to the US proposal on nuclear disarmament’, Bulletin of the Atomic Scientists, April 19, 2019, https://thebulletin.org/2019/04/sidetrack-or-kickstart-how-to-respond-to-the-us-proposal-on-nuclear-disarmament/ (accessed 11 Oct. 2019).
49 U.S. Department of State, Bureau of International Security and Nonproliferation (2019), ‘Creating an Environment for Nuclear Disarmament Working Group Meets in Wilton Park’, Press Release, 27 November 2019, https://www.state.gov/creating-an-environment-for-nuclear-disarmament-working-group-meets-in-wilton-park/ (accessed 11 Dec. 2019).
50 For a definition of ‘extended deterrence’, see Anderson, J. V., Larsen, J. A., Holdorf, P. M. (2013), Extended Deterrence and Allied Assurance: Key Concepts and Current Challenges for U.S. Policy, INSS Occasional Paper, US Air Force Institute for National Security Studies, USAF Academy, Colorado, https://www.usafa.edu/app/uploads/OCP69.pdf (accessed 29 Oct. 2019).
51 Borrie, J. (2020), ‘Human Rationality in Nuclear Deterrence’, in Unal, B., Afina, Y. and Lewis, P. (eds) (2020), Perspectives on Nuclear Deterrence in the 21st Century, Research Paper, London: Royal Institute of International Affairs, p. 8, https://www.chathamhouse.org/sites/default/files/2020-04-20-nuclear-deterrence-unal-et-al.pdf (accessed 19 May 2020).
52 Preamble, NPT.
53 Jervis, R. (2009), ‘The Dustbin of History: Mutual Assured Destruction’, Foreign Policy, 9 November 2009, https://foreignpolicy.com/2009/
11/09/the-dustbin-of-history-mutual-assured-destruction/ (accessed 16 Oct. 2019).
54 Meyer, P. (2018), Folding the Umbrella: Nuclear Allies, the NPT and the Ban Treaty, Policy Brief No. 58, Asia Pacific Leadership Network for Nuclear Non-Proliferation and Disarmament, Toda Peace Institute, http://www.isodarco.it/courses/kyrenia19/doc/policy-Brief-No%2058-
Folding-the-Umbrella.pdf (accessed 11 Oct. 2019).
55 Tannenwald, N. (1999), ‘The Nuclear Taboo: The United States and the Normative Basis of Nuclear Non-Use’, International Organization, 53(1), pp. 433–468, https://www.jstor.org/stable/2601286?seq=1 (accessed 6 Jan. 2020).
56 For example, the 2018 Brussels Summit Declaration stipulates that while the ‘fundamental purpose of NATO’s nuclear capability is to preserve peace, prevent coercion, and deter aggression’, the ‘circumstances in which NATO might have to use nuclear weapons are extremely remote’. This demonstrates that while nuclear weapons remain at the heart of the Alliance’s security, NATO perceives the use of nuclear weapons as highly exceptional. See NATO (2018), ‘Brussels Summit Declaration’, https://www.nato.int/cps/en/natohq/official_texts_156624.htm (accessed 16 Oct. 2019).
57 NATO (2016), ‘Remarks by NATO Deputy Secretary General Rose Gottemoeller during a panel discussion on Perspectives for a World Free from Nuclear Weapons at Vatican City’, https://www.nato.int/cps/en/natohq/opinions_148789.htm?selectedLocale=en (accessed 11 Oct. 2019). For a discussion on the TPNW and nuclear umbrella arrangements, see Human Rights Program at Harvard Law School (2018), Nuclear Umbrella Arrangements and the Treaty on the Prohibition of Nuclear Weapons, International Human Rights Clinic, Harvard Law School, http://hrp.law.harvard.edu/wp-content/uploads/2018/06/Nuclear_Umbrella_Arrangements_Treaty_Prohibition.pdf (accessed 24 Oct. 2019).
58 Ibid.
59 Benoît Pelopidas explored whether extended deterrence could be either a sufficient or a necessary condition for non-proliferation, and argues that it has been neither. See Pelopidas, B. (2015), ‘A Bet Portrayed as a Certainty: Reassessing the Added Deterrent Value of Nuclear Weapons’, in Shultz, G. P. and Goodby, J. E. (eds) (2015), The War That Must Never Be Fought: Dilemmas of Nuclear Deterrence, Stanford, CA: Hoover Institution Press.
60 International Court of Justice (1996), Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, Reports of Judgments, Advisory Opinions and Orders, 8 July 1996, https://www.icj-cij.org/files/case-related/95/095-19960708-ADV-01-00-EN.pdf (accessed 29 Oct. 2019).
61 Egeland, K. (2019), ‘Arms, Influence and the Treaty on the Prohibition of Nuclear Weapons’, Survival, 61(3), p. 67, doi: 10.1080/00396338.2019.1614786 (accessed 29 Oct. 2019); see also: Hayashi, N. (2014), ‘Legality Under Jus ad Bellum of the Threat of Use of Nuclear Weapons’ in Nystuen. G., Casey-Maslen, S. and Bersagel, A. G. (eds) (2014), Nuclear Weapons under International Law, Cambridge: Cambridge University Press.
62 The term ‘collective self-defence’ is often interpreted as ‘the well-established UN Charter right to States to defend other States.’ See Pothelet, E. (2018), ‘U.S. Military’s “Collective Self-Defense” of Non-State Partner Forces: What Does International Law Say?’, Just Security, 26 October 2018, https://www.justsecurity.org/61232/collective-self-defense-partner-forces-international-law-say/ (accessed 12 Mar. 2020).
63 It is a rule of customary international law that the basis of the exercise of the right to self-defence lies on the conditions of (1) necessity, and (2) proportionality, as established by the ICJ in the Nicaragua v. United States of America case of 1986: International Court of Justice (1986), Case Concerning the Military and Paramilitary Activities in and Against Nicaragua (Nicaragua v. United States of America), Judgment, Reports of Judgments, Advisory Opinions and Orders, 27 June 1986, https://www.icj-cij.org/files/case-related/70/070-19860627-JUD-01-00-EN.pdf (accessed 12 Mar. 2020).
64 International Court of Justice (1996), Legality of the Threat or Use of Nuclear Weapons, paras 47–48: ‘If the envisaged use of force is itself unlawful, the stated readiness to use it would be a threat prohibited under Article 2, paragraph 4’ of the UN Charter.
65 Ibid., para. 48.
66 Ibid., para. 42.
67 For an in-depth discussion on the legal consequences of a nuclear detonation under international humanitarian law, see Maresca, L. and Mitchell, E. (2015), ‘The human costs and legal consequences of nuclear weapons under international humanitarian law’, International Review of the Red Cross, 97(899), pp. 621–645, https://international-review.icrc.org/sites/default/files/irc97_8.pdf (accessed 17 Mar. 2020).
68 Norwegian People’s Aid, Nuclear Weapons Ban Monitor 2019, TPNW Status and Compliance, p.47, https://banmonitor.org/files/Nuclear_Weapons_Ban_Monitor_2019.pdf (accessed 28 Nov. 2019).
69 Wan, W. (2019), Nuclear Risk Reduction, United Nations Institute for Disarmament Research, https://unidir.org/files/publications/pdfs/nuclear-risk-reduction-a-framework-for-analysis-en-809.pdf (accessed 28 Nov. 2019).