Legality of the Threat or Use of Nuclear Weapons ICJ 3 is a landmark international law case, where the International Court of Justice gave an advisory opinion stating that while the threat or use of nuclear weapons would generally be contrary to international humanitarian law, it cannot be concluded whether or not such a threat or use of nuclear weapons would be lawful in extreme circumstances where the very survival of a state would be at stake. The Court held that there is no source of international law that explicitly authorises or prohibits the threat or use of nuclear weapons but such threat or use must be in conformity with the UN Charter and principles of international humanitarian law. The Court also concluded that there was a general obligation to pursue nuclear disarmament.
The World Health Organization requested the opinion on 3 September 1993, but it was initially refused because the WHO was acting outside its legal capacity (ultra vires). The United Nations General Assembly requested another opinion in December 1994, which was accepted by the Court in January 1995. As well as determining the illegality of nuclear weapon use, the court discussed the proper role of international judicial bodies, the ICJ's advisory function, international humanitarian law (jus in bello), and rules governing the use of force (jus ad bellum). It explored the status of "Lotus approach", and employed the concept of non liquet. There were also strategic questions such as the legality of the practice of nuclear deterrence or the meaning of Article VI of the 1968 Treaty on the Non-Proliferation of Nuclear Weapons.
The possibility of outlawing the use of nuclear weapons in an armed conflict was raised on 30 June 1950, by the Dutch representative to the International Law Commission (ILC), , who suggested this "would in itself be an advance".Yearbook of the ILC, 1950, vol. I, p. 131 In addition, the Polish government requested this issue to be examined by the ILC as a crime against the peace of mankind.Yearbook of the ILC, 1950, vol. 1, p. 162, Yearbook of the ILC, Vol. II 1950 p. 250 However, the issue was delayed during the Cold War.
The New START treaty was an agreement by both the US and Russian governments to limit the deploying of nuclear ballistic missiles. Signed in 2010 and entering into force on February 5, 2011, the treaty was extended in 2021 for another five years before officially expiring on February 5, 2026.
Request of the World Health Organization
An advisory opinion on this issue was originally requested by the World Health Organization (WHO) on 3 September 1993:"ICJ Press releases on the Legality of the Use by a State of Nuclear Weapons in Armed Conflict " - General List No. 93 (1993-1996)
The ICJ considered the WHO's request, in a case known as the Legality of the Use by a State of Nuclear Weapons in Armed Conflict (General List No. 93), and also known as the WHO Nuclear Weapons case, between 1993 and 1996. The ICJ fixed 10 June 1994 as the time limit for written submissions, but after receiving many written and oral submissions, later extended this date to 20 September 1994. After considering the case the Court refused to give an advisory opinion on the WHO question. On 8 July 1996 it held, by 11 votes to three, that the question did not fall within the scope of WHO's activities, as is required by Article 96(2) of the UN Charter.ICJ Press release on the Legality of the threat or use of nuclear weapons - ICJ Advisory Opinion 8 July 1996, ICJ General List No. 93
Request of the UN General Assembly
On 15 December 1994 the UN General Assembly adopted resolution A/RES/49/75K. This asked the ICJ urgently to render its advisory opinion on the following question:
The resolution, submitted to the Court on 19 December 1994, was adopted by 78 states voting in favour, 43 against, 38 abstaining and 26 not voting.United Nations Bibliographic Information System Dag Hammarskjold Library Voting record search: UN Symbol: A/RES/49/75K
The General Assembly had considered asking a similar question in the autumn of 1993, at the instigation of the Non-Aligned Movement (NAM), which ultimately did not push its request that year. NAM was more willing the following year, in the face of written statements submitted in the WHO proceedings from a number of nuclear-weapon states indicating strong views to the effect that the WHO lacked competence in the matter. The Court subsequently fixed 20 June 1995 as the filing date for written statements.
Altogether, 42 states participated in the written phase of the pleadings, the largest number ever to join in proceedings before the Court. Of the five declared nuclear weapon states (the P5), only the People's Republic of China did not participate. Of the three "threshold" nuclear-weapon states, only India participated. Many of the participants were developing states which had not previously contributed to proceedings before the ICJ, a reflection perhaps of the unparalleled interest in this matter and the growing willingness of developing states to engage in international judicial proceedings in the "post-colonial" period.
Oral hearings were held from 30 October to 15 November 1995. Twenty-two states participated: Australia, Egypt, France, Germany, Indonesia, Mexico, Iran, Italy, Japan, Malaysia, New Zealand, Philippines, Qatar, Russian Federation, San Marino, Samoa, Marshall Islands, Solomon Islands, Costa Rica, United Kingdom, United States, Zimbabwe; as did the WHO. The secretariat of the UN did not appear, but filed with the Court a dossier explaining the history of resolution 49/75K. Each state was allocated 90 minutes to make its statement. On 8 July 1996, nearly eight months after the close of the oral phase, the ICJ rendered its opinion.
Decision of the International Court of Justice
Composition of the Court
The ICJ is composed of fifteen judges elected to nine year terms by the UN General Assembly and the UN Security Council. The court's "advisory opinion" can be requested only by specific United Nations organisations, and is inherently non-binding under the Statute of the court.
The fifteen judges asked to give their advisory opinion regarding the legality of the threat or use of nuclear weapons were:
President Mohammed Bedjaoui Vice-president Stephen M. Schwebel Judge Shigeru Oda Judge Gilbert Guillaume Judge Mohammed Shahabuddeen Judge Christopher Weeramantry Judge Raymond Ranjeva Judge Shi Jiuyong Judge Carl-August Fleischhauer Judge Abdul G. Koroma Judge Géza Herczegh Judge Judge Luigi Ferrari Bravo Judge Rosalyn Higgins Judge Andrés Aguilar Mawdsley(died before the decisionSee footnote 61 to the dissenting opinion of Judge Weeramantry)
Registrar Eduardo Valencia Ospina
Court's analysis
Deterrence and "threat" The court considered the matter of deterrence, which involves a threat to use nuclear weapons under certain circumstances on a potential enemy or an enemy. Was such a threat illegal? The court decided, with some judges dissenting, that, if a threatened retaliatory strike was consistent with military necessity and proportionality, it would not necessarily be illegal. (Judgement paragraphs 37–50)
The legality of the possession of nuclear weapons The court then considered the legality of the possession, as opposed to actual use, of nuclear weapons. The Court looked at various treaties, including the UN Charter, and found no treaty language that specifically forbade the possession of nuclear weapons in a categorical way.
The UN Charter was examined in paragraphs 37–50 (paragraph 37: "The Court will now address the question of the legality or illegality of recourse to nuclear weapons in the light of the provisions of the Charter relating to the threat or use of force"). Paragraph 39 mentions: "These provisions [i.e. those of the Charter] do not refer to specific weapons. They apply to any use of force, regardless of the weapons employed. The Charter neither expressly prohibits, nor permits, the use of any specific weapon, including nuclear weapons. 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."
Treaties were examined in paragraphs 53–63 (paragraph 53: "The Court must therefore now examine whether there is any prohibition of recourse to nuclear weapons as such; it will first ascertain whether there is a conventional prescription to this effect"), as part of the law applicable in situations of armed conflict (paragraph 51, first sentence: "Having dealt with the Charter provisions relating to the threat or use of force, the Court will now turn to the law applicable in situations of armed conflict"). In particular, with respect to "the argument [that] has been advanced that nuclear weapons should be treated in the same way as poisoned weapons", the Court concluded that "it does not seem to the Court that the use of nuclear weapons can be regarded as specifically prohibited on the basis of the [...] provisions of the Second Hague Declaration of 1899, the Regulations annexed to the Hague Convention IV of 1907 or the 1925 Protocol" (paragraphs 54 and 56)". It was also argued by some that the Hague Conventions concerning the use of bacteriological or chemical weapons would also apply to nuclear weapons, but the Court was unable to adopt this argument ("The Court does not find any specific prohibition of recourse to nuclear weapons in treaties expressly prohibiting the use of certain weapons of mass destruction", paragraph 57 in fine).
With respect to treaties that "deal [...] exclusively with acquisition, manufacture, possession, deployment and testing of nuclear weapons, without specifically addressing their threat or use," the Court notes that those treaties "certainly point to an increasing concern in the international community with these weapons; the Court concludes from this that these treaties could therefore be seen as foreshadowing a future general prohibition of the use of such weapons, but they do not constitute such a prohibition by themselves" (paragraph 62). Also, regarding regional treaties prohibiting recourse, namely those of Tlatelolco (Latin America) and Rarotonga (South Pacific) the Court notes that while those "testify to a growing awareness of the need to liberate the community of States and the international public from the dangers resulting from the existence of nuclear weapons", "[i]t [i.e. the Court] does not, however, view these elements as amounting to a comprehensive and universal conventional prohibition on the use, or the threat of use, of those weapons as such." (paragraph 63).
Customary international law also provided insufficient evidence that the possession of nuclear weapons had come to be universally regarded as illegal.
Ultimately, the court was unable to find an opinio juris (that is, legal consensus) that nuclear weapons are illegal to possess. (paragraph 65) However, in practice, nuclear weapons have not been used in war since 1945 and there have been numerous UN resolutions condemning their use (however, such resolutions are not universally supported—most notably, the nuclear powers object to them).(paragraph 68–73) The ICJ did not find that these facts demonstrated a new and clear customary law absolutely forbidding nuclear weapons.