The Nuclear Weapons Advisory Opinion (General Assembly Request)

International Court of Justice Advisory Opinion: Legality of the Threat or Use of Nuclear Weapons
Year of Decision: 1996. 
Court: International Court of Justice.

Background to the case

The General Assembly of the United Nations asked the Court to provide its legal opinion on the following question “Is the threat or use of nuclear weapons in any circumstances permitted under international law?” In 1993, two years previously, the World Health Organization had asked the Court a similar question on the legality of the use nuclear weapons under international law. The Court declined to answer because the Court held that the  World Health Organization did not have the competence to ask the Court that particular question.

Questions before the Court:

The Court discussed two procedural questions:

(1) Did the Court have the competence to give an advisory opinion based on a request of the General Assembly? In other words, did the General Assembly have the competence to ask the Court for an advisory opinion on the above question?

(2) If yes, were there any reasons that would compel the Court to decline to exercise it’s jurisdiction?

The Court also discussed five substantive questions:

(3) Did treaty or customary law authorize  the use of nuclear weapons?

(4) Did treaty or customary law contain a “comprehensive and universal” prohibition on the threat and use of nuclear weapons?

(5) Should the threat or use of nuclear weapons be compatible with international humanitarian law and other undertakings of the law?

(6) Will the threat or use of nuclear weapons be lawful in self defense in situations where the very survival of the State is at stake?

(7) Is there an obligation on States to work towards nuclear disarmament?

Relevant Findings of the Court:

(1) Did the Court have the jurisdiction to give a reply to the request of the General Assembly?

The Court concludes that it had the jurisdiction to respond to the question for the following reasons:

(1) Firstly, the Court says that it has the competence under Article 65 (1) of the Statute of the ICJ to provide an advisory opinion, when it is requested by a “competent organ of the United Nations”.

The Court may give an advisory opinion on any legal question at the request of whatever body may be authorized by or in accordance with the Charter of the United Nations to make such a request.

(2) Secondly, the General Assembly is a “competent organ” because it is authorized by  Article 96 (1) of the United Nations Charter to request an advisory opinion from the Court. The Court says that:

The General Assembly or the Security Council may request the International Court of Justice to give an advisory opinion on any legal question.

(3) Thirdly, together with Articles 10, 11, and 13, Article 96(1) of the UN Charter gives the General Assembly the competence to request an advisory opinion on “any legal question”.

(4) Some states said that this particular question is not a legal question but a political question. The Court reiterates that it has consistently held that the mere fact that a question before the Court may also have “political dimensions” or “political consequences” will not deprive the question of its legal character, or affect the competence of the Court to reply. The Court concludes that this question is a legal question. In other words, it is “framed in terms of the law and rais(ing) problems of international law…(which) are by their very nature susceptible of a reply based on law”. Thus, the Court concludes it had the relevant jurisdiction to respond to this question.

(2)  Even if the Court had the relevant competence, should it use its discretion and refuse to respond to the question? 

The Court concludes that there are no “compelling reasons” to refuse to provide a response to the advisory opinion.

(1)  The Court agrees that even if it has the competence to give an opinion, it can still refuse to respond to an advisory opinion based on the discretion it has under Article 65 (1) of the Statute. If you recall, Article 65 (1) says that “the Court may give an advisory opinion…”.

(2) Some States argued that Court  should use its discretion to refuse to give an opinion. This is because, they argued, for example, that the question posed by the General Assembly was abstract, any response would undermine progress already made in disarmament, and that in answering the question posed the Court  would be taking upon itself a law-making capacity.The Court rejects all of these arguments in detail. (see paras 10 – 19). It says that:

The Court’s opinion is given not to States, but to the organ which is entitled to request it; the reply of the Court, itself an ‘organ of the United Nations’, represents its participation in the activities of the Organization, and in principle, should not be refused. 

(3) The Court confirms that it had previously never exercised its discretion under Article 65 (1) to refuse to answer a question. The Court says that  only “compelling reasons” could lead to such a refusal and that, in this situation, there are no “compelling reasons” which would lead the Court to refuse.

(3) Did customary or treaty law authorize the use of nuclear weapons?

The Court concludes that neither customary law, nor treaty law, explicitly authorizes the use of nuclear weapons (para 52).

Yet, it highlights that explicit authorization is not required because the illegality on the threat or use of nuclear weapons does not stem from the lack of specific authorization, but on a specifically formulated prohibition (the general principle is found in more detail in the Lotus case).

Next, it went on to examine if customary or treaty law prohibits the threat or use of nuclear weapons.

(4) Did treaty or customary law prohibit the threat and use of nuclear weapons?

The Court concludes that there is no comprehensive and universal prohibition on the threat or use of nuclear weapons either in treat or customary law.

(1) In terms of treaty law, some States argued that the use of nuclear weapons would violate the right to life and other treaty-based human rights, prohibition on genocide, and rules relating to the protection of the environment. The Court says that none of these treaties provide a “universal and comprehensive” prohibition on the use of nuclear weapons (see paras 24-34).

(2) Then, the Court says that the  “most directly relevant applicable law” is the UN Charter provisions relating to the use of force and those laws that govern armed conflict. However, it finds that both of these legal regimes also do not expressly prohibit, nor permit, the use of nuclear weapons. The Court finds that:

(a) Articles 2(4), 42, and 51 of the UN Charter that relates to the legality on the use of force, is silent on the specific weapons that can be used when using force (for more, see prohibitions on the use of force).

(b) International humanitarian law treaties (part of those laws governing armed conflict), including the Hague Convention IV of 1907 and the Geneva Protocol of 1925 have been understood in State practice, as not covering nuclear weapons.  Similarly, other humanitarian law treaties governing weapons of mass destruction, like the Biological and Chemical Weapons Conventions, also do not contain prohibitions on the use of nuclear weapons.

(c) The Court also points out that those treaties that specifically relate to nuclear weapons (para 58) only limit its use, but does not support a general prohibition.

(3) In terms of customary law, the Court finds that the opinio juris on the prohibition of the use of nuclear weapons differs amongst States, as reflected in the content and voting patterns of General Assembly resolutions, their views on deterrence and the non use of nuclear weapons in the recent past (para 64 -72 and see post on opinio juris). The Court finds that:

…the members of the international community are profoundly divided on the matter of whether non-recourse to nuclear weapons over the past 50 years constitutes the expression of opinio juris. Under these circumstances the Court does not consider itself able to find that there is such an opinio juris… The emergence, as lex lata, of a customary rule specifically prohibiting the use of nuclear weapons as such is hampered by the continuing tensions between the nascent opinio juris on the one hand, and the still strong adherence to the practice of deterrence on the other. 

(4) The Court concludes that there is no comprehensive and universal prohibitions on the threat or use of nuclear weapons under treaty law or customary law.

(5) Even if international law does not explicitly prohibit the threat or use of nuclear weapons, is their use regulated under international law? 

Thus far, the Court has concluded that there are no provisions in international law that authorizes or prohibits the threat or use of nuclear weapons by States. The Court now goes a step further to examine if the threat or use of these weapons is regulated under international law. In other words, should its use be compatible with the requirements of international law applicable in armed conflict (which includes international humanitarian law) and the UN charter?

The Court finds as follows:

(1)  UN Charter: Court had  established that the UN Charter did not permit or prohibit the use any type of weapons. However, it finds that for the a threat or use of force in self defense to be lawful under Article 51 of the UN Charter, the use of nuclear weapons must be necessary and proportionate to the armed attack against which self-defense is exercised. The Court says that the use of nuclear weapons may be proportionate in certain circumstances (the Court does not specify the circumstances).

(2) International humanitarian law: The Court goes on to hold that even if the threat or use of nuclear weapons is lawful under the UN Charter (in other words, when it is necessary and proportionate), it must still meet the requirements of laws regulating armed conflicts, including international humanitarian law and principles relating to neutrality.

NB: Points 1 and 2 above were uncontroversial,  but the individual judges were divided amongst themselves on points 3 and 4 below.

(3)   The Court finds that it cannot conclude that the recourse of nuclear weapons “would be illegal in any circumstances”or if the use of nuclear weapons was inherently and totally incompatible with international humanitarian law.

…In view of the unique characteristics of nuclear weapons… the use of such weapons in fact seems scarcely reconcilable with respect for such requirements (relating to distinction and suffering). Nevertheless, the Court considers that it does not have sufficient elements to enable it to conclude with certainty that the use of nuclear weapons would necessarily be at variance with the principles and rules of law applicable in armed conflict in any circumstance… (emphasis added).

This was reaffirmed in the Court’s conclusion when it held that nuclear weapons were generally, and not absolutely, contrary to international law applicable in armed conflicts:

It follows from the above-mentioned requirements that the threat or use of nuclear weapons would generally be contrary to the rules of international law applicable in armed conflict, and in particular the principles and rules of humanitarian law (emphasis added).

(4) The Court also finds that it could not reach a conclusion on the legality or illegality of the use of nuclear weapons in “an extreme case of self defense”.  The Court highlights the “fundamental right of every State to survival” and holds that,

…in view of the present state of international law viewed as a whole… (and base  on) the elements of fact at its disposal, the Court is led to observe that it cannot reach a definitive conclusion as to the legality (i.e. whether the threat or use of nuclear weapons would be lawful or unlawful) of the use of nuclear weapons by a State in an extreme circumstance of self-defense, in which, its very survival would be at stake. 

(5) The Court didn’t elaborate on what would constitute an extreme case of self-defense nor address whether a State having nuclear weapons (a nuclear State) can use it in the defense of another non-nuclear State when that second State’s very existence is threatened. See further here.

(7) Is there an obligation on States for nuclear disarmament?

The Court finds that there is an obligation “to pursue in good faith and bring to a conclusion negotiations leading to disarmament…” (paras 98 – 103),

Note: Other interesting aspects of the judgement that haven’t been dealt with in this post, in detail, includes paragraphs relating to the applicability of human rights and environmental law in times of armed conflict (paras 24 – 34), policy of deterrence (para 48, 66 – 67, 73), and General Assembly’s contribution to the progressive development of customary law

 Further reading:
Additional notes:
  • *The General Assembly has requested 15 advisory opinions from the ICJ.
  • *The Permanent Court of International Justice refused to provide an advisory opinion in Status of Eastern Carelia
  • *For a difference between advisory opinions and contentious cases click here.

* indicates material that are freely accessible.

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