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Part II Collective Security and the Non-Use of Force, Ch.15 Use of Force: Justiciability and Admissibility

A Mark Weisburd

From: The Oxford Handbook of the Use of Force in International Law

Edited By: Marc Weller

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2022. All Rights Reserved. Subscriber: null; date: 09 December 2022

Weapons, nuclear — International peace and security — Witnesses — Self-defence — Ships / vessels

(p. 329) Chapter 15  Use of Force:

Justiciability and Admissibility

I.  Introduction

The International Court of Justice (ICJ) is the principal judicial organ of the United Nations.1 When legal issues arise from the use of force, therefore, the ICJ may be asked to address the law governing the use of force. There are, however, limits on the ICJ’s capacity to affect this body of law. This chapter addresses one set of such potential limitations: restrictions on the ICJ’s capacity to act which arise from problems of admissibility or justiciability.

Considering admissibility first, it must initially be noted that the term is difficult to define clearly. The closest the Court has come to defining admissibility its observation that objections to admissibility normally take the form of an assertion that, even if the Court has jurisdiction and the facts stated by the applicant state are assumed to be correct, nonetheless there are reasons why the Court should not (p. 330) proceed to an examination of the merits.2 However, some of the Court’s decisions add content to the concept.

While the Court has called several cases inadmissible, in which it found no concrete dispute between the parties,3 and treated similarly a case involving a dispute affecting the rights of a non-party state,4 the case with the most bearing on this discussion is the judgment of the Permanent Court of International Justice in Free Zones of Upper Savoy and the District of Gex (Switzerland v. France).5 In that case, the parties had asked the Court to, inter alia, devise rules for a customs regime affecting parts of their territories.6 The Court refused to do so, characterizing such a task as unsuitable to the role of a court of justice.7 It went on to observe that:

the settlement of such matters is not a question of law, but is a matter depending on the interplay of economic interests on which no Government can afford to be controlled by an outside organ. Such questions are outside the sphere in which a Court of Justice, concerned with the application of rules of law, can help in the solution of disputes between two States.8

Two aspects of this language stand out. First, the Court considered the resolution of economic questions as not susceptible to control by legal rules, and therefore not a task for a judicial body. Secondly, the Court saw the matter as one so important that any government would necessarily have to reserve final decisions to itself; as to this second point, the Court’s language implies that governments’ maintaining control of such decisions was not only inevitable but, more fundamentally, proper.

Thus, we have three different bases for a determination that a case is not admissible: first, that the parties’ dispute cannot be called a legal dispute; secondly, that the issue is not one resolvable by the application of legal rules; and, thirdly, that the issue is one that necessarily must be addressed by an institution other than the Court.

The Court has never addressed justiciability as such. However, that term too refers to the question whether there are reasons why a court ought not decide a particular case over which it has jurisdiction. The three categories of admissibility specified in the preceding paragraph also describe situations in which a case could be called non-justiciable. Indeed, the only difference between the two ideas in the practice of the Court would appear to be that, formally, admissibility issues are raised by respondents as preliminary objections, while the Court can find itself (p. 331) confronting justiciability issues at any stage of the proceedings. The discussion that follows therefore will treat the categories in the foregoing paragraph as applicable to both justiciability and admissibility.

This discussion will focus on the last two of those categories. That is, it will consider disputes involving the use of force that cannot be decided without the exercise of non-legal judgement. The chapter will also address cases that, though not outside the Court’s jurisdiction, would be more properly resolved by a different body.

The problem presented when judges are asked to resolve an issue that turns on non-legal considerations is one with which lawyers should be generally familiar. However, as will be discussed in greater detail later, cases addressing the use of force can present unique difficulties.

The question of whether the Court or some other institution ought properly to deal with a given matter implicates the authority of the Security Council of the United Nations. Under the Charter, the Security Council has primary responsibility for the maintenance of international peace and security;9 further, members of the UN are obliged to comply with its decisions,10 and it is authorized to decide11 among a virtually unlimited menu of tools12 how best to respond to a situation it concludes is a threat to the peace, breach of the peace, or act of aggression.13 Given the very broad scope of the Security Council’s authority, it is important to understand how the Court deals with cases that arguably involve that authority.

The discussion which follows will examine these matters in greater detail.

II.  The ICJ and Cases Requiring the Exercise of Non-Legal Judgement

A.  Introduction

The Court may be called upon to decide cases requiring the exercise of non-legal judgement in at least two sets of circumstances. First, the nature of a particular dispute may make it difficult for someone without special training even to recount events. Secondly, there will be cases in which the problem is not so much (p. 332) disagreement over historical facts as it is that of evaluating those facts by applying specialized knowledge of some subject other than law.

The first of these types of questions is not unique to use of force issues; it is not uncommon for triers of fact to face the task of assessing the testimony of witnesses. However, the unusual difficulties in obtaining facts regarding military operations can be exacerbated when the significance of the facts is not apparent to someone without military expertise. Such cases shade over into those involving the second sort of question as, for example, in a use of force case in which it is necessary to evaluate behaviour according to standards employed by persons with experience in the problems of making military decisions. If decisions in such cases are made by persons lacking the necessary specialized knowledge, the results may be doubtful. Indeed, even the Court in Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. US) has acknowledged that its making determinations requiring the exercise of military judgement could be problematic.14

The discussion now turns to the cases arguably raising questions about the Court’s capacity to determine and evaluate fact questions in the use of force context. It should be stressed that the Court discussed military considerations in resolving what it denominated as an admissibility issue only in Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. US).15 However, it addressed issues analogous to admissibility in Legality of Threat or Use of Nuclear Weapons.16 In the other three cases examined, as the following discussion will show, it was forced to deal with issues arguably requiring the evaluation of military considerations; these cases therefore provide further understanding of the Court’s approach in such matters, albeit not in the context of admissibility.

1.  Corfu Channel (UK v. Albania)

In this case,17 the UK instituted proceedings against Albania alleging that Albania was responsible for the harm done to certain Royal Navy warships, which while traversing the Corfu Channel in October 1946, struck mines.18 The case turned on (p. 333) the questions of whether Albania, or Yugoslavia acting with Albania, had laid the mines and, if that question could not be answered, whether the mines could have been laid without the knowledge of the Albanian government.19

Resolving the case required the Court to decide a number of issues of fact. After hearing the parties’ witnesses, it appointed, on its own initiative, a committee of neutral naval officers to investigate and report on certain disputed factual questions.20 These questions related to crucial issues in the case, in particular, whether the mines could have been laid without Albania’s knowledge.21 In subsequently deciding that the Albanian government must have known of the minelaying, the Court relied heavily on the experts’ reports.22

In this case, the Court actively sought to supplement the parties’ evidence in order to address particular fact questions. It should also be noted, however, that the necessary evidence was apparently not difficult to obtain and the naval officers who assessed the evidence for the Court had only to answer relatively objective questions.23 This case therefore differed from one where evidence was difficult to obtain, or where assessment of the evidence was less straightforward.

2.  Nicaragua v. US

This case presented use of force issues different in kind from those in Corfu Channel. Nicaragua alleged that the US had violated international law by supporting the so-called contra rebels’ efforts to overthrow Nicaragua’s government and by mining Nicaraguan ports. The US raised numerous preliminary objections, among them the argument that the Court should treat the case as inadmissible ‘in consideration of the inability of the judicial function to deal with situations involving ongoing conflict’, referring to the difficulty in resolving factual issues in such cases.24

The Court rejected this argument, stating that a case was not inadmissible simply because one of the parties bore the burden of proof on an issue as to which evidence might well be unavailable:

it is the litigant seeking to establish a fact who bears the burden of proving it; and in cases where evidence may not be forthcoming, a submission may in the judgment be rejected as unproved, but is not to be ruled out as inadmissible in limine on the basis of an anticipated lack of proof.25

(p. 334) The Court confronted another sort of question during the merits phase of this case.26 The US did not appear in that phase, but its earlier pleadings made clear that it did not seriously contest the broad outlines of Nicaragua’s factual allegations regarding US actions. Rather, it argued that those actions amounted to lawful self-defence or, more precisely, as collective self-defence in concert with El Salvador against Nicaragua’s support for an insurgency in El Salvador.27 In that connection, the US argued that considering that defence would require the Court to consider military matters beyond its expertise. The Court observed that it would not need to consider such issues if the legal prerequisites for the self-defence claim were absent.28 In fact, it reached that conclusion.29

Nonetheless, the Court did not in fact refrain from an evaluation of military considerations. In its discussion of the facts of the case, the Court observed that, while the US had in 1981 raised with Nicaragua concerns regarding arms flows from Nicaragua to El Salvador, it had refused, citing security considerations, to provide Nicaragua with evidence of its claims.30 For this reason, the Court stated, it could not assess the value of this evidence. It went on to observe:

the Court would remark that, if [evidence of smuggling] really existed, the United States could be expected to have taken advantage of it in order to forestall or disrupt the traffic observed; it could presumably for example arrange for the deployment of a strong patrol force in El Salvador and Honduras, along the frontiers of these States with Nicaragua. It is difficult to accept that it should have continued to carry out military and paramilitary activities against Nicaragua if their only purpose was, as alleged, to serve as a riposte in the exercise of the right of collective self-defence.31

There were similarities between the Court’s attitude on this issue and its treatment of Article XXI in the treaty between the US and Nicaragua,32 which formed the basis of the Court’s jurisdiction in the case. That article provided that ‘the present Treaty shall not preclude the application of measures [by a party]…necessary to protect its essential security interests.’33

The Court held that it had the authority to determine whether particular actions by the parties to this treaty could be considered ‘necessary to protect…essential security interests’. The Court justified this conclusion by noting, first, that it had jurisdiction to interpret Article XXI and, secondly, that the language in question, unlike that in some other treaties, did not expressly leave to the state concerned the determination whether a given action was ‘necessary for the protection of its essential security interests.’34 The Court then held:

Taking into account the whole situation of the United States in relation to Central America, so far as the Court is informed of it (and even assuming that the justification of self-defence, (p. 335) which the Court has rejected on the legal level, had some validity on the political level), the Court considers that the mining of Nicaraguan ports, and the direct attacks on ports and oil installations, cannot possibly be justified as ‘necessary’ to protect the essential security interests of the United States.35

In this case, the Court’s analysis in its preliminary objections judgment was incomplete. In contrast to the situation in the Corfu Channel case, obtaining the evidence necessary to the US self-defence argument was difficult. That argument centred on allegations regarding the behaviour of the applicant state. The best evidence on the issues raised by that defence was necessarily in the possession of Nicaragua, which would have no incentive to produce the evidence and every incentive to misrepresent it. While the US might have had available information obtained through espionage, it could not reveal that information without taking significant risks. Thus, these evidence-access problems meant that the US, had it proceeded with the case, would have had to either abandon its self-defence claim as not being able to be proved or compromise its intelligence-collection methods. The Court’s reliance on burden of proof concepts in dealing with this situation was unsatisfactory. This was not a situation in which the party with the evidence problem had invoked the jurisdiction of the Court; rather, the US was an unwilling litigant. Nor was this case comparable to one in a domestic court in which a defendant could rely on subpoena power and discovery to obtain evidence necessary to a defence. Arguably, a case in which a respondent state would be unable to offer a defence, except at unreasonable cost, would seem to be one the Court should hesitate to hear, that is, treat as inadmissible, even assuming that it had jurisdiction and that the applicant’s allegations were accurate.

Elements of the Court’s merits judgment in this case were also questionable. Its assertion that if the US truly had evidence of arms being smuggled into El Salvador through Honduras, it would have arranged for the deployment of a strong patrol force assumes that such a deployment would have been possible. Whether that was true, however, depended on issues of military feasibility: whether such patrolling was possible in the light of the nature and the extent of the terrain to be patrolled and the availability of the necessary human and material resources. In assuming the possibility of such patrolling, the Court engaged in the evaluation of military considerations, an activity that it implied it would avoid.

The Court’s purporting to determine the essential security interests of the US in its analysis of Article XXI of the Friendship Treaty between Nicaragua and the US was also problematic. The Court’s discussion of its jurisdiction and its parsing of the treaty language were not relevant to the key point, that is, whether the Court, relying on legal analysis, could itself determine a state’s essential security interests. To the extent that the Court was unable to do so, and in fact relied on its own (p. 336) political and military assessment, it, once again, was engaging in an activity requiring non-judicial expertise.

3.  Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion

This advisory opinion36 responded to the following question from the General Assembly: ‘Is the threat or use of nuclear weapons under any circumstances permitted under international law?’ While the concept of admissibility as such does not seem applicable to the Court’s advisory jurisdiction, the Court in this case was faced with the argument that it should decline to give the requested opinion, lest its conclusions amount to ‘hypothetical or speculative declarations outside the scope of its judicial function’.37 In rejecting this argument, the Court stated:

The Court does not consider that…it would necessarily have to write ‘scenarios’, to study various types of nuclear weapons and to evaluate highly complex and controversial technological, strategic and scientific information. The Court will simply address the issues arising in all their aspects by applying the legal rules relevant to the situation.38

That is, the Court seemed to consider whether to render an advisory opinion as involving considerations analogous to those which, in its contentious jurisdiction, would be matters of admissibility.

On the substance of the case, the Court was quite cautious. Its focus was the behaviour of states. It noted that, regarding arms control, states had chosen to label certain weapons as prohibited rather than to label others as authorized. It found no prohibition of nuclear weapons either in existing treaties or deriving from Security Council actions.39 It likewise found no such prohibition in customary international law in the light of states’ deep differences of opinion and practice on the issue.40 It further held that international humanitarian law, though applicable to the use of nuclear weapons, did not forbid their use in all circumstances.41 The Court went on to observe that it could not ‘lose sight of the fundamental right of every State to survival, and thus its right to resort to self-defence…when its survival is at stake’42 and took note as well of the ‘policy of deterrence’ applied by ‘an appreciable section of the international community’.43 It concluded that it could not ‘reach a definitive conclusion’ on the question presented to it.44 In the dispositif, the Court’s answer to the General Assembly’s question stated that the use of nuclear weapons was generally illegal, but added that the Court could not say that such weapons could not lawfully be used ‘in an extreme circumstance of self-defence, in which the very survival of a State would be at stake’; this part of the dispositif was adopted only by the president’s casting vote.45

(p. 337) The Court’s approach in this case was strikingly different from that it employed in the Military and Paramilitary Activities case. The Nuclear Weapons advisory opinion could be said to involve a pure question of law, while the earlier case turned on factual questions. Nonetheless, the Court made its own evaluations of military issues in the Military and Paramilitary Activities case while refraining from doing so in the advisory opinion. In particular, it did not attempt to determine the circumstances in which the use of nuclear weapons in self-defence could be said to be necessary. Given the importance of the issue, it is perhaps not surprising that the Court was unwilling to go further than it did in the absence of an international consensus.

4.  Oil Platforms (Iran v. US)

In this case,46 Iran sought reparations from the US because of US attacks on certain Iranian oil platforms in the Persian Gulf in October 1987 and April 1988. The attacks took place during the Iran–Iraq war, in the course of which the belligerents carried out numerous attacks in the Persian Gulf on ships flying the flags of neutral states.47 The US argued that both of its sets of attacks were acts of lawful self-defence. The US characterized the 1987 attacks as a defensive response to attacks, attributed by the US to Iran, on US merchant vessels, in particular on the ship Sea Isle City.48 It characterized the 1988 attacks as acts of self-defence after a US naval vessel struck a mine, allegedly laid by Iran in international waters.49 It appears from the Court’s decision that there was at least strong evidence that the laying of the mine struck by the warship was not an isolated incident, but an element of what the US argued was Iran’s ‘general practice of using mines to attack neutral shipping’.50

The Court rejected the US claims of self-defence. The Court had two grounds for its conclusion as to the 1987 attacks. First, the Court held that the evidence provided by the US to prove Iranian responsibility for the attack on the merchant vessel was insufficient.51 Secondly, it stated that the Sea Isle City incident was not, in any event, an armed attack on the US, since the missile employed in that attack was so inaccurate that it could only have been directed at the general area in which the Sea Isle City happened to be, not specifically at that vessel.52 Regarding the 1988 attacks, the Court held that mining of the naval vessel likewise did not support a claim of self-defence by the US, relying in part on its determination that the evidence of Iranian responsibility was ‘highly suggestive, but not conclusive’,53 and also by observing:

The Court does not exclude the possibility that the mining of a single military vessel might be sufficient to bring into play the ‘inherent right of self-defence’; but in view of all the circumstances, including the inconclusiveness of the evidence of Iran’s responsibility for the mining… the Court is unable to hold that the attacks on the…platforms have been shown (p. 338) to have been justifiably made in response to an armed attack on the United States by Iran, in the form of the mining…54

The Court also considered the scale of the 1988 attacks, ‘as a response to the mining, by an unidentified agency, of a single United States warship, which was severely damaged but not sunk, and without loss of life’ violated the principle of proportionality.55 The Court did not address the US allegation that Iran made a practice of mining shipping lanes in order to attack neutral shipping.

The Court’s analysis of the attribution issue in connection with the 1987 attacks seems to assume that military commanders in the field should not attribute uses of force to particular states absent supporting evidence adequate for use in a court. As Judge Buergenthal observed in his separate opinion, the Court’s approach did not consider the question to be whether, considering all the facts available to US decision-makers at the time, it was reasonable for the US to act as it did.56 Expanding upon Judge Buergenthal’s point, the Court could be said to have failed to take military considerations into account in a case in which they were at least arguably crucial.

Also, the Court reached a doubtful conclusion in holding that the incidents upon which the US relied could not be called armed attacks on the US because they could not be said to have been directed specifically at US vessels. By this logic, if a state directs attacks on other states in such a way that it cannot predict which other states will be harmed by those attacks, none of the victims can be said to have been a victim of an armed attack and therefore none could claim a right to self-defence. This amounts to treating attacks directed indiscriminately at a number of states as equivalent to a situation in which there are no attacks at all. Again, the issue would appear to involve military considerations, that is, how a commander could reasonably respond in the situation faced by the US. While it might be that the Court should be understood to have held that the rule it applied was binding whatever the dilemma confronting a commander attempting to defend ships in the position of the Sea Isle City, its opinion could also be read as failing to come to grips with this dilemma.

There are also problems with the Court’s treatment of the US arguments regarding the 1988 attacks. First, the Court held that the mining of the US warship that triggered the response did not amount to an armed attack. However, it appears that the US presented at least some evidence that Iran was regularly mining international waters;57 that is, while only one ship may have struck a mine, Iran had laid others. Perhaps laying one mine in international waters is not an armed attack on all vessels using those waters, but if a state lays enough mines, presumably at some point it has created so great a danger that the minelaying must be an armed attack on international shipping, regardless of the number of ships that actually strike mines.

(p. 339) The characterization of the 1988 US attacks as a disproportionate response to the mining of a single vessel is a mistake at both the practical and legal levels. As a practical matter, a naval commander confronted with evidence of minelaying has to determine how to address the threat of future harm the mines present, however limited the damage that may have already been incurred. There is also strong legal authority that evaluating the proportionality element of the doctrine of self-defence requires comparing the defender’s actions to the harm to be prevented from happening, not to that which has already occurred.58

As with its treatment of the 1987 attacks, the Court’s approach here arguably suggests a failure to confront the military considerations involved in evaluating the 1988 attacks. The military problem the US faced was deciding how to respond, not only to past harms, but to the future dangers presented by Iran’s apparent strategy of mining the Gulf. The Court’s failure even to acknowledge the existence of this military problem raises doubts as to whether the judges truly understood the actual situation they were attempting to assess.

Taken together, the Court’s mistakes in its analysis of this case demonstrate the rationale for treating the analysis of military considerations as generally beyond the competence of a court.

5.  Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory

This advisory opinion59 resulted from a General Assembly request for an assessment of the legality of Israel’s construction of a barrier complex intended to forestall terrorist infiltration from the occupied Palestinian territories into Israel proper.60 After an extensive discussion, the Court concluded that Israel’s actions violated international law in a number of respects.61 Once it had determined that Israel’s actions violated international law, the Court considered arguments that could be seen as affirmative defences, that is, assertions of the form ‘Even if Israel’s actions would otherwise be in violation of international law, additional circumstances render those actions lawful.’ In this connection, the Court first addressed the contention that the Israeli barrier complex should be seen as a lawful act of self-defence. It rejected that argument, asserting that a state could invoke the right of self-defence as set out in Article 51 of the UN Charter only in response to actions by another state; since the threats against which Israel sought to protect itself did not emanate from a state, Article 51 was irrelevant.62 The Court also considered and rejected the argument that Israel could invoke the defence of necessity.63 The Court observed that the necessity defence was only available if the action at issue was ‘the only way for the State to (p. 340) safeguard an essential interest against a grave and imminent peril’.64 Its only explanation for its rejection of that defence in this situation was its statement that it was ‘not convinced that the construction of the wall along the route chosen was the only means to safeguard the interests of Israel against the peril which it has invoked as justification for that construction’.65 The Court acknowledged the security problems on which Israel’s reference to Article 51 was based, but did not address them in any detail.66

One might have expected the Court to support its conclusion that Israel had failed to demonstrate the necessity of the barrier complex by reference to alternative measures available to Israel, especially in the light of its acknowledgement of Israel’s security problems. The Court did not do so. Judge Buergenthal took issue with the Court’s approach in a vigorous separate opinion, arguing that the Court could not properly address the situation without an evidentiary record addressing the problems Israel faced and the options available to it and that it therefore should have declined to render the opinion.67 With or without such evidence, analysis of such an argument would in any event require consideration of military factors. The Court’s conclusory treatment of the issue explained neither how it performed that analysis nor why it saw itself as competent to do so.

III.  Cases Involving Matters Arguably within the Province of the Security Council

A.  Introduction

The preceding section addressed admissibility problems posed by cases presenting issues not readily justiciable. The discussion now turns to a second kind of admissibility issue: the Court’s position in cases in which its actions might conflict with decisions of the Security Council.

There have been no instances in which both bodies addressed the same situation, but did so inconsistently. However, there have been developments that could be the seed of future conflicts. First, the Court’s explanations for its decisions to proceed with a case despite some degree of Security Council involvement are formulated in (p. 341) a way that leaves open the possibility of conflict. Also, the Court has taken a quite different view of the right of self-defence from that of the Security Council; in the light of the primary responsibility of the Security Council for the maintenance of international peace and security, one could argue that the Court should defer to the Council on such questions. A discussion of the cases will make these points clearer.

B.  Cases

1.  Nicaragua v. US

In its preliminary objections,68 the US had argued that the case was inadmissible because the responsibility of dealing with alleged unlawful uses of force belonged exclusively to the political organs of the UN and that, in the light of the Security Council’s refusal to act on Nicaragua’s application, Nicaragua’s taking the case to the Court amounted to asking the Court to review the Council’s action.69

At the outset, it must be acknowledged that there was no prospect that the Security Council would address the situation in Nicaragua, given the fundamental disagreements among permanent members. However, the Court’s rejection of the US arguments did not turn on that fact, focusing instead on other factors. It noted70 that the Security Council had not objected to its order for provisional measures in United States Diplomatic and Consular Staff in Tehran.71 It observed that, while the Charter expressly forbids the General Assembly to make recommendations when the Security Council is dealing with an issue, it imposes no such restrictions on the Court, which, the Court stated, reflects its crucial role in peaceful dispute settlement.72 It also rejected the US characterization of the matter as involving an alleged unlawful use of force, noting that no notice of this conflict had been given to the Council and asserting that ‘it is clear that the complaint of Nicaragua is not about an ongoing armed conflict between it and the United States …’73 The Court also pointed out that the Charter vested in the Security Council primary but not exclusive responsibility for dealing with uses of force, stating that ‘the Council has functions of a political nature assigned to it, whereas the Court exercises purely judicial functions. Both organs can therefore perform their separate, but complementary functions with respect to the same events’.74 It stressed that the Court had never avoided a case because of its political elements or because it involved serious elements of the use of force.75 It dismissed as irrelevant the distinction the US drew between cases involving uses of force in the past and those involving uses of force (p. 342) contemporaneously, and argued that it could not be said to be hearing an appeal of the Security Council’s actions, in that ‘the Court is not asked to say that the Security Council was wrong in its decision, nor that there was anything inconsistent with law in the way in which the members of the Council employed their right to vote.’76

The Court’s reasoning in this judgment is suspect. It relied on its decision in the Diplomatic and Consular Staff in Tehran case for the general proposition that the Court and the Council can consider a matter simultaneously. However, in the Tehran case, the Court was at pains to demonstrate that, as a matter of fact, its activities were not interfering with those of the Council.77 The Court carried out no similar analysis in this case. The Court put weight on the US failure to report its actions to the Council; while that failure may raise issues about US compliance with Article 51 of the Charter, it seems irrelevant in this context, since the Council’s authority does not depend on a report being made. Further, while it may have been clear that Nicaragua’s complaint involved no ‘ongoing armed conflict’, it was hardly clear that the situation giving rise to the complaint was not an armed conflict, especially in the light of the US defence’s focus on the internal armed conflict in El Salvador. The reference to the Court’s history of not avoiding cases of this sort did not acknowledge that the Court had never before confronted a case of this type; in this connection, if the distinction between current and past uses of force was irrelevant, it would have been helpful for the Court to explain why this was so.

Aside from the foregoing, there are three especially serious weaknesses in the Court’s analysis. The first is the Court’s apparent conclusion that the Council’s primary responsibility for the maintenance of international peace and security imposes no limitations on the Court’s activity. Even though, as the Court noted, there is no language in the Charter regarding the Court analogous to the limits imposed on the General Assembly by Article 12,78 the Charter’s designating the Council as having primary responsibility for the maintenance of international peace and security must mean that all other organs of the UN must defer to the Council when it is exercising that responsibility. Otherwise, the designation of the Council as primary loses its meaning. The foregoing does not explain how the functions of the Court and Council are to be reconciled, but neither did the Court make any attempt to determine the consequences of the Council having ‘primary responsibility’.

To be sure, the Court asserted that both it and the Council could perform their separate functions with regard to the same events, since the Council’s functions were political while those of the Court were purely judicial.79 That assertion was the second serious problem in this opinion. The Court neither considered the possibility that its judgment could, as a practical matter, impede a particular course of action the Council had chosen, nor addressed the implications of such a conflict. It simply (p. 343) relied on the formal political/legal distinction to justify its position. The Court’s third mistake, similar to its second, was its rejection of the argument that it was, in effect, hearing an appeal from an action of the Security Council. The Court’s disingenuous claim that it was not entertaining an appeal since it was not passing judgement on the legal validity of the Council’s actions, once again, relied on a formal political/legal distinction and ignored the potential practical effects of its judgment.

2.  Questions of Interpretation and Application of the 1971 Montreal Convention Arising from the Aerial Incident at Lockerbie (Libyan Arab Jamahiriya v. US)

This case80 derived from the bombing of a US-registered aircraft while over the town of Lockerbie, Scotland, in 1988. Having become convinced that identified Libyan agents had planted the bomb, the UK and the US demanded that Libya, among other things, surrender those agents for trial.81 In January 1992, the Security Council adopted a resolution urging Libya to comply with the demands;82 after Libya had failed to comply, the Council adopted legally binding resolutions on 31 March 1992 and 11 November 1993, requiring Libya to surrender the suspects. The Council also imposed sanctions on Libya pending compliance.83 Libya on 3 March 1992 had filed an application with the Court seeking a declaration that the so-called Montreal Convention84 was applicable to the matter, that Libya had complied with its obligations under that treaty while the US and the UK had not, and that the two countries were obliged to refrain from threats of force and ‘to respect Libya’s right not to have the [Montreal] Convention set aside …’85

The Court denied Libya’s requests for provisional measures in orders of 14 April 1992.86 These orders relied on the broad authority of the Council; the Court expressly stated that Libya’s obligation under Article 25 of the Charter, read in conjunction with (p. 344) Article 103, obliged it to comply with the Council’s 31 March resolution and superseded any obligations under the Montreal Convention. It also stated that, whatever Convention rights Libya may have had prior to the adoption of that resolution, those rights were not appropriate for protection by provisional measures, given that resolution. The Court further noted that such measures would be likely to impair the respondents’ rights under the resolution.87

The Court’s approach to the Council’s resolutions was quite different in its 1998 judgments rejecting the respondents’ preliminary objections. Both respondents had argued that the case was without object in that, whatever the situation might be under the Montreal Convention, the Security Council’s resolutions superseded that treaty and any rights Libya might have enjoyed under it.88 The Court acknowledged that this argument could properly be labelled a preliminary objection, but observed that the parties disagreed as to whether the objection possessed an exclusively preliminary character.89 The Court concluded that it did not, stressing that the very reasons offered by the respondents in support of their objections showed that Libya’s rights on the merits would in fact be the subject of any judgment even though, in form, it would be a decision not to address the merits.90

This case reinforces the concerns raised by the Court’s reasoning in Military and Paramilitary Activities. This becomes clear when one compares the reasoning in the 1992 orders denying Libya’s request for provisional measures with that in the 1998 preliminary objections judgments. In the 1992 orders, the Court took it as established, prima facie, that Security Council resolutions clearly required Libya to extradite the two suspects and that they prevailed over the Montreal Convention.91 It would seem, therefore, that the only questions left were whether this reading of the resolutions was correct and whether the Council was authorized to adopt the resolutions. If the resolutions in fact had the effect which the respondents contended and the Council had the requisite authority, the respondents were correct that Libya’s claim was without object. The Court’s 1998 judgment rightly observed that resolving these matters would have the same effect as a decision on the merits. However, if the Court was correct in asserting that this conclusion meant that the argument could not be raised as a preliminary objection, then the Court can never uphold any preliminary objection not directed at jurisdiction, since all such (p. 345) objections necessarily go to what could be called the merits of the case.92 Further, unless there was some doubt about the legal effect of the Council’s resolutions, the claim was in fact without object. The Court’s refusal to uphold the preliminary objections thus implied that the legal effect of the resolutions was not clear, which is puzzling in the light of its 1992 pronouncements regarding the Council’s authority. The result is difficult to understand, and could even be read as a claim by the Court that it had the authority to treat Council resolutions as unlawful.

3.  Self-defence

As noted previously,93 the Court asserted in Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory94 that a state could invoke the right of self-defence as justifying military operations on the territory of another state only if it was defending itself against that state; threats from non-state actors could not justify such operations.95 The Court reiterated this position in Armed Activities on the Territory of the Congo (DRC v. Uganda).96 The case arose from military operations carried out by Uganda within the Congo.97 Among other justifications for its conduct, Uganda asserted that it was acting in self-defence.98 The Court’s reasons for rejecting this defence included Uganda’s failure to prove that the Congolese government was responsible for the attacks on Ugandan territory that had emanated from the territory of the Congo.99

The problem with the treatment of self-defence in these cases is that it is inconsistent with Security Council resolutions which recognized100 and reaffirmed101 the right of self-defence in the context of the attacks on the US on 11 September 2001. Since those attacks, of course, were not perpetrated by states, the position of the Court on this matter is flatly contrary to that taken by the Security Council.102 Indeed, judges writing separately in those cases drew attention to just this point.103 One would think that the Security Council’s understanding of the concept of self-defence would have some bearing on the Court’s analysis, but the Court neither followed the Council nor explained why it did not.

(p. 346) IV.  Conclusion

In conclusion, the Court has faced few cases that it could not decide without engaging in what amounted to analyses requiring military, rather than legal, expertise. However, in those few cases, it has shown little willingness to apply the concept of inadmissibility or to deal in some other way with arguable justiciability issues. Aside from its action in the Corfu Channel case, it has not sought assistance to evaluate military considerations.104 If the Court’s attitude towards this subject stays constant, it is difficult to imagine a case that the Court will decline to hear solely because its resolution would require such an evaluation.

The Court has also characterized its authority vis-à-vis the Security Council in a way that arguably would permit it to question the Council’s actions. If that is in fact the Court’s position, it could have significant effects on the functioning of the UN.

The Court’s treatment of these issues presents the risk that it will reach results in particular use of force cases that are suspect legally and ill-advised as a practical matter. More fundamentally, they force states to consider how much sense it makes to take seriously the Court’s pronouncements on issues involving the use of force.


UN Charter, Art 92.

Oil Platforms (Iran v. US), Merits, ICJ Rep 2003, 161, 177 (6 Nov).

See eg Northern Cameroons (Cameroon v. UK), Preliminary Objections, ICJ Rep 1963, 15; Nuclear Tests (Australia v. France), Judgment, ICJ Rep 1974, 253; Nuclear Tests (New Zealand v. France), Judgment, ICJ Rep 1974, 457.

Monetary Gold Removed from Rome in 1943 (Italy v. France, UK and US), ICJ Rep 1954 19. Compare Certain Phosphate Lands in Nauru (Nauru v. Australia), ICJ Rep 1992, 240.

PCIJ, Ser A/B, No 46.

At 160–1.

At 162.

At 161–2.

UN Charter, Art 24.

10  Art 25.

11  Art 39.

12  Arts 40–9.

13  Art 39.

14  Merits, ICJ Rep 1986, 14. In that case, the US sought to respond to allegations of US violations of international law by characterizing its actions as an exercise of the right of self-defence. As the Court noted, the US argued that its raising the issue of self-defence required determining whether the US faced the necessity of using force, and that such a determination involves a pronouncement on political and military matters, not a question of a kind that a court can usefully attempt to answer, para 34. The Court responded to this concern by stating that, in the light of the posture of the case, its resolution of the dispute would not necessarily involve it in any evaluation of military considerations, para 35. This response suggests that the Court agreed that it might face difficulties if it attempted to engage in such an evaluation.

15  Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. US), Jurisdiction of the Court and Admissibility of the Application, ICJ Rep 1984, para 99.

16  Advisory Opinion, ICJ Rep 1996, para 15.

17  ICJ Rep 1949, 4.

18  At 6, 12–13.

19  At 15–16.

20  At 7–9.

21  Corfu Channel (UK v. Albania), Order made on 17 Dec 1948, ICJ Rep 1948, 124, 124–6 (hereafter Corfu Channel, Order of 17 Dec).

22  Legality of Threat or Use of Nuclear Weapons, Advisory Opinion, paras 20–2.

23  eg the range of visibility from a given location at a specific time and day, Corfu Channel, Order of 17 Dec, 125, or whether whoever laid the mines in question could have acted without being observed by the Albanian authorities, Corfu Channel, Order of 17 Dec, 126.

24  Nicaragua, Jurisdiction of the Court and Admissibility of the Application, para 99.

25  Nicaragua, para 99.

26  Para 99.

27  Paras 15, 126.

28  See discussion at n 14.

29  Nicaragua, paras 195, 211, 230.

30  Para 155.

31  Para 156.

32  Treaty of Friendship, Commerce and Navigation Between the United States of America and the Republic of Nicaragua, Managua, 21 Jan 1956, 367 UNTS 3.

33  Art XXI.

34  See Nicaragua, paras 222, 282.

35  Para 282.

36  ICJ Rep 1996, 226.

37  Para 15.

38  Para 15.

39  Paras 52–63.

40  Paras 64–73.

41  Paras 74–95.

42  Para 96.

43  Para 96.

44  Para 97.

45  Para 105(2)E. Each of the 14 judges wrote separate opinions in this case; they were even more divided in their methods of analysis than they were in their voting. See ICJ Rep 1996, 268–593.

46  Merits, ICJ Rep 2003, 161.

47  Paras 23–4.

48  Para 48.

49  Para 67.

50  Paras 67–9.

51  Paras 50–61.

52  Para 64.

53  Para 71.

54  Para 72.

55  Para 77.

56  Oil Platforms (Iran v. US), Merits, Separate Opinion of Judge Buergenthal, ICJ Rep 2003, 270, para 40.

57  See Legality of the Threat or Use of Nuclear Weapons, paras 67–9.

58  See Noam Lubell, Extraterritorial Use of Force Against Non-State Actors (Oxford: Oxford University Press, 2010), 65 and authorities therein cited.

59  Advisory Opinion, ICJ Rep 2004, 136.

60  Paras 66–82.

61  Paras 86–137.

62  Paras 138–9.

63  Para 140.

64  Para 140, quoting Art 25 of the International Law Commission’s Articles on Responsibility of States for Internationally Wrongful Acts, Annex, GA Res 56/83 (28 Jan 2002), A/RES/56/83.

65  Para 140.

66  Para 141.

67  Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Separate Opinion of Judge Buergenthal, ICJ Rep 2004, 240.

68  See n 15.

69  Nicaragua, Jurisdiction of the Court and Admissibility of the Application, paras 89, 91.

70  Para 93.

71  ICJ Rep 1980, 3.

72  Nicaragua, Jurisdiction of the Court and Admissibility of the Application, para 93.

73  Para 94.

74  Para 95.

75  Para 96.

76  Paras 97–8.

77  See n 71, paras 40–4.

78  See n 24, para 93.

79  Para 95.

80  ICJ Rep 1998, 115.

81  Letter dated 20 December 1991 from the Permanent Representative of the United Kingdom of Great Britain and Northern Ireland to the United Nations addressed to the Secretary-General (31 Dec 1991), S/23307; Letter dated 20 December 1991 from the Permanent Representative of the United States of America to the United Nations addressed to the Secretary-General (31 Dec 1991), S/23308.

82  SC Res 731 (21 Jan 1992), S/RES/731.

83  SC Res 748 (31 Mar 1992), S/RES/748; SC Res 883 (21 Jan 1992), S/RES/731.

84  Convention for the Suppression of Unlawful Acts Against the Safety of Civil Aviation, Montreal, 23 Sept 1971, 974 UNTS 177.

85  Questions of Interpretation and Application of the 1971 Montreal Convention Arising from the Aerial Incident at Lockerbie (Libyan Arab Jamahiriya v. UK), Preliminary Objections, ICJ Rep 1998, 9 [1]‌; Questions of Interpretation and Application of the 1971 Montreal Convention Arising from the Aerial Incident at Lockerbie (Libyan Arab Jamahiriya v. US), Preliminary Objections, ICJ Rep 1998, 115 [1].

86  Questions of Interpretation and Application of the 1971 Montreal Convention Arising from the Aerial Incident at Lockerbie (Libyan Arab Jamahiriya v. UK), Provisional Measures, ICJ Rep 1992, 3; Questions of Interpretation and Application of the 1971 Montreal Convention Arising from the Aerial Incident at Lockerbie (Libyan Arab Jamahiriya v. US), Provisional Measures, ICJ Rep 1992, 114.

87  Libya v. UK, Provisional Measures, paras 39–41; Libya v. US, Provisional Measures, paras 42–4.

88  Libya v. UK, Preliminary Objections, para 46; Libya v. US, Preliminary Objections, paras 39–40.

89  Libya v. UK, Preliminary Objections, 47–8; Libya v. US, Preliminary Objections, paras 46–7.

90  Libya v. UK, Preliminary Objections, para 50 (corresponding discussion in Libya v. US is substantially identical, Libya v. US, Preliminary Objections, para 49).

91  Libya v. UK, Provisional Measures, ICJ Rep 1992, 3, paras 42–4; Libya v. US, Provisional Measures, ICJ Rep 1992, 114 paras 39–41.

92  Accord, Shabtai Rosenne, The Law and Practice of the International Court (4th edn, Leiden: Martinus Nijhoff, 2006), vol II, 891.

93  See text at n 61.

94  ICJ Rep 2004, 136.

95  Paras 138–9.

96  ICJ Rep 2005, 168.

97  Para 28.

98  Para 118.

99  Paras 146–7.

100  SC Res 1368 (12 Sept 2001), S/RES/1368.

101  SC Res 1373 (28 Sept 2001), S/RES/1373.

102  See also Theresa Reinold, ‘State Weakness, Irregular Warfare, and the Right to Self-Defence Post 9/11’ (2011) 105 American Journal of International Law 244, 260–1.

103  Advisory Opinion on the Israeli Wall, Separate Opinion of Judge Koojimans, ICJ Rep 2003, 219, para 35 and Declaration of Judge Buergenthal, paras 5–6; Congo v. Uganda, Separate Opinion of Judge Koojimans, ICJ Rep 2005, 306, paras 28–9 and Separate Opinion of Judge Simma, ICJ Rep 2005, 334, paras 10–13.

104  The (closely divided) Court effectively deferred in its Nuclear Weapons advisory opinion to the strategic judgements of the nuclear weapons states. One might wonder whether the fact that an opposite result would have been ignored, thereby humiliating the Court, affected the deliberations.