Nuclear Weapons and the International Criminal Court

ILPI Publications, Policy Papers

Why an explicit reference to nuclear weapons in the definition of War Crimes under the Statutes of the International Criminal Court should not be a priority.

Over the years it has often been suggested that existing norms restricting the use of nuclear weapons may be strengthened by the adoption of a legal mechanism that explicitly criminalizes the use of these weapons. The notion underpinning this line of thinking is that individuals responsible for a decision to launch a nuclear attack – be they state leaders or terrorists – would be more reluctant to do so if they knew they would be held personally accountable for that decision. In addition, such a focus on the actual use of nuclear weapons could serve to strengthen the humanitarian perspective of the nuclear weapons debate by linking it directly to the basic principles of International Humanitarian Law (IHL). One could also imagine that the added stigmatization of nuclear weapons resulting from such a process would make the mere possession of nuclear weapons less desirable, hence making it a catalyst for progress towards the ultimate goal of full nuclear disarmament. Advocates of this view have suggested inter alia that such an explicit criminalization of the use of nuclear weapons could be done through an amendment of the Statutes of the International Criminal Court (ICC). More specifically, the idea has been to include a reference to the use of nuclear weapons under the definition of War Crimes in the Rome Statutes.

While such a move may seem appealing to some, this paper argues that efforts aimed at promoting such an amendment to the ICC statute are ill-advised, not least because the ICC already prohibits the use of weapons that would violate the rules on distinction and proportionality. An explicit reference to nuclear weapons use would create the impression that such use is not covered by the existing provisions in the ICC. In addition, such a move would constitute a legislative undertaking that might undermine the ICC’s legitimacy in the long run.

The question of whether or not to include the use of weapons of mass destruction (WMDs) in the list of illegal weapons in the Rome Statutes was discussed from early phases of the ICC negotiations. During the final rounds of negotiations of the Statutes in 1998, proponents of an inclusion contended that the use of both chemical and biological weapons were already prohibited under international law and that the use of nuclear weapons had been deemed to be “generally contrary to the rules of international law” by the International Court of Justice in 1996.[1] To the dismay of several states and NGOs, the proposal was eventually dropped in order to reach agreement. The failure to include any specific reference to any WMDs was openly lamented by a number of states,[2] including Mexico who was particularly concerned with the issue of nuclear weapons and signalled that it would bring the issue up again at the first review conference of the statutes – to be held 7 years after the entry-into-force of the treaty.

The ICC-statute entered into force in 2002, and the first Review Conference of the Statutes was held in Kampala, Uganda in 2010. In the preparations for the Review Conference, the nuclear weapons issue resurfaced, and at the 8th Session of the Assembly of States Parties in November 2009 Mexico presented a draft resolution for an amendment to the Statutes, by which the use or threat to use nuclear weapons would be included in the definition of war crimes under Article 8 of the Statutes.[3] Once again, however, the proposal received only limited support, and Mexico eventually withdrew the draft resolution as it became clear that consensus would not be reached.[4] Strictly speaking, the proposal would only require two-thirds majority of the State Parties to be adopted, but in order to take effect the amendment would require the ratification of seven-eights of the State Parties. And even then, it would only be binding on those states that ratified it.[5]

The meeting and the Mexican proposal passed almost unnoticed among the nuclear abolition NGOs, but those who did engage in the debate picked up the banners from 1998 and argued in favour of including a reference to nuclear weapons in the Statutes. As one of the most vocal groups, The Parliamentarians for Nuclear Non-proliferation and Disarmament (PNND) disseminated an open letter to all States Parties in which they endorsed the Mexican draft resolution.[6] Mary Kaldor of the London School of Economics was among the academics that voiced support for the ICC route in the run-up to the 2009 meeting. In an article published in August 2009, she noted that “[t]he threat or use of nuclear weapons should be treated as a war crime or a crime against humanity and should be included in the jurisdiction of the International Criminal Court”.[7] In Kaldor’s view, such an amendment could contribute significantly to reframing the nuclear disarmament debate in a more humanitarian discourse. Similarly, Marie Glasius of the University of Amsterdam called for anti-nuclear activists to join forces with other ICC-focused NGOs and push for formal criminalization of the use of nuclear weapons through the Statutes of the ICC.[8]

An Unnecessary Detour
For anti-nuclear activists, the ICC-track may present itself as a tempting step towards nuclear elimination. For one, the actual amendment of the statutes could be minuscule (the proposed Mexican amendments contains a total of nine words). Secondly, amendments to the Rome Statutes can be approved by a two-thirds majority of the States Parties, which in theory could make the non-nuclear-armed states secure adoption of such an amendment without the support of the nuclear-armed states. Third, since any use of nuclear weapons would have catastrophic humanitarian consequences,[9] and, therefore, with near certainty violate international humanitarian law, the explicit prohibition of such use under the ICC Statutes could be presented as a codification of an already existing legal norm.

While these arguments may have an appealing face-validity, they also largely miss the point. Most importantly, perhaps; they leave the impression that use of weapons of mass destruction would not be a war crime unless this is explicitly stated in the Statutes. This, of course, is wrong. Article 8 in the ICC statutes already prohibits violations of the rule on distinction and the rule on proportionality. Practically all conceivable usages of weapons of mass destruction, including nuclear weapons, would necessarily violate at least one if not both of these core rules of IHL. It is, in this regard, worth noting that for example the Yugoslavia Tribunal convicted a person for the use of cluster munitions before these weapons were banned, because of their inherently indiscriminate effects.[10] An explicit reference to nuclear weapons in the statutes could thus be deemed not only superfluous, but even as undermining the existing ICC statute rules on distinction and proportionbality.

Secondly, while it is true that an amendment could be very limited in scope, and that amendments can be adopted by a two-thirds majority of the States Parties, these amendments would only take effect if seven-eights of the States Parties ratify them. And even if that is achieved, amendment to Articles 5, 6, 7 or 8 would not be binding on those who do not ratify it. In other words, the nuclear-armed States Parties to the ICC (UK and France) could choose to opt out of the new amendment. The ICC would consequently have no jurisdiction over the matter in these countries. Nor will the court have jurisdiction over the other nuclear-armed states, since none of them are currently parties to the Statutes. This does not, of course, mean that the process of adopting such an amendment would be politically irrelevant, something the cases of land-mines and cluster munitions may serve to illustrate. One could expect such a process to generate considerable political attention, and it would also provide an opportunity to reframe the discourse in a more humanitarian direction, as Mary Kaldor suggested. Nevertheless, the option to opt out any amendments to Articles 5  to 8 does provide an indication of the inherent limitations associated with using the ICC as a route towards the explicit prohibition of the use of nuclear weapons.

A third argument that should caution against a process aimed at including a reference to nuclear weapons in the Rome Statutes relates to the ICC more conceptually. As a regime, the ICC was not designed to create international law – it was designed as a mechanism under which to prosecute and judge in accordance with it. Consequently, if the use of nuclear weapons is to be included in the Statutes, the illegality under international law of such use, for those states that “opted in”, should be indisputable. The standard approach to ensuring agreement on illegality of specific arms is to negotiate an international legal instrument that explicitly prohibits the use of the weapons in question. This has been the case for the other weapon categories that were included under Article 8 in the Statutes.[11] This is also the case for chemical and biological weapons, both of which are prohibited under comprehensive international treaties. This would make the case for including chemical and biological weapons under Article 8 stronger than for including nuclear weapons,[12] since nuclear weapons lack such an agreed comprehensive prohibition.

With this as a backdrop, it is tempting to conclude that the actors working to promote a ban on nuclear weapons – be they States or civil society – should refrain from using the ICC as a route to establish such a ban. This is primarily because such a move would be largely superfluous; The ICC already prohibits violations of the principle of distinction and the principle of proportionality, which in practice would encompass most conceivable usages of nuclear weapons. Secondly, it would use the ICC as a vehicle for establishing international legislation, something that may undermine its legitimacy in the long run.  If the use of nuclear weapons is to be included as a War Crime in the ICC Statutes, such a move should be preceded by the negotiation of a treaty that explicitly bans all use of nuclear weapons.

[1] See the Art. 105, (1), E of the 1996 Advisory Opinion of the ICJ; <>

[2] Including India, Mexico, Cuba, Sudan on behalf of the Arab group, Egypt, Bangladesh and Benin. For a more detailed account of the process see J.Burroughs (1999) <>

[3] The Draft Resulotion uses the term ’employ’ instead of ’use’: “Employing nuclear weapons or threatening to employ nuclear weapons”. There is an inherent problem in the wording of this proposal, as it seems to confuse the key legal concept of jus ad bellum and jus in bello. The ‘threat to employ’ is irrelevant in terms of IHL, and should not be included in the ICC Statutes. See separate ILPI policy papers for more on the distinction between jus ad bellum and jus in bello. The full text of the Mexican draft resolution can be found on page 9 of the meeting report: <>

[4] Journal of International Criminal Justice 8 (2010), 1219^1243.

[5] See Article 121 of the Statutes for details on the procedure for amendments.

[6] <>

[7] <>

[8] <>

[9] This language is drawn from the Outcome Document of the 8th Review Conference of the Nuclear Non-Proliferation Treaty in 2010.

[10] The Martić-case, ITCY, 2007, <>

[11] Including, but not limited to, poison and expanding bullets.

[12] See e.g. Kara Allen with Scott Spence and Rocío Escauriaza Leal (2011), “Chemical and biological weapons use in the Rome Statute: a case for change”, <>