25.1  Located in the Peace Palace at The Hague, the International Court of Justice was established by the United Nations Charter as a forum for settling international disputes. It is a principal organ of the UN, replacing the Permanent Court of International Justice which had functioned since 1922. It is now one of a number of international courts,¹ but it remains ‘the principal judicial organ of the United Nations’.² Most of the detailed provisions relating to its functions and powers are to be found in the Statute of the Court which is annexed to the UN Charter and forms an integral part of it.³ While few diplomats in the course of their careers are likely to appear before the Court as representatives of their governments, the use of the Court to settle disputes, and the impact of the Court’s decisions more generally, are significant features of the conduct of international affairs.

25.2  The Court’s role is to decide, in accordance with international law, disputes which are submitted to it by States and to give advisory opinions on questions referred to it by certain United Nations organs and specialized agencies. The first of these two kinds of cases are referred to as contentious cases, the second as advisory proceedings.

25.3  Only States may be parties to contentious cases before the Court. Individuals, corporations, and organizations cannot. Although the Court is sometimes referred to as the ‘World Court’, it is not a supreme court which national courts or individuals can use as a last resort. Nor is it an appeal court for any other international tribunal. The United Nations cannot itself bring a case against a State in its own judicial organ; however, a United Nations organ may initiate advisory proceedings if it has a right to do so.⁴

25.4  A State may be a party to a contentious case only if it is a member of the United Nations, or has become a party to the Statute of the Court, or has accepted its jurisdiction under certain conditions. All members of the United Nations are parties to the Statute by virtue of their UN membership. A State which is not a UN member may become a party to the Statute on conditions determined by the General Assembly upon the recommendation of the Security Council. Before they became UN members, Japan, Liechtenstein, San Marino, Nauru, and Switzerland were all parties to the Statute of the Court, in accordance with conditions (the same in each case) set by General Assembly resolution.⁵ At present, however, all parties to the Statute of the Court are members of the United Nations.⁶

25.5  The fact that a State is a party to the Court’s Statute does not mean that the Court has jurisdiction to hear any case against it. The Court may hear a case only if the States concerned have agreed to accept its jurisdiction. There is no prescribed form in which the consent of a State to the Court’s jurisdiction must be expressed, and consent may be given either after a particular dispute has (p. 527) arisen or in advance. The Court has jurisdiction over cases brought to it in one or more of three ways: (i) if the parties have agreed to refer the particular case to the Court, (ii) if the parties have previously agreed in a treaty to refer such disputes to the Court, or (iii) if each party has made a declaration accepting the jurisdiction of the Court as compulsory in the event of a dispute with another State which has made a similar declaration (Article 36.1 and 36.2 of the Statute).

25.6  Thus, the first way in which a case may be brought before the Court is by the consent of the parties to refer that case. Usually, but not invariably, this consent is given in the form of a written agreement or treaty, known as a ‘special agreement’ or compromis.⁷ No particular form of agreement has to be used, so long as the consent is unequivocally given.⁸ Consent may be deduced from acts of a State. A State may file an application in the Court and invite another State to consent to the Court’s jurisdiction. For example, Djibouti made an application to the Court in 2006 against France alleging that France was in violation of a treaty of mutual cooperation for not assisting with a Djibouti investigation of the murder of a French judge in Djibouti; France, rather surprisingly, sent in a letter of acceptance agreeing to the Court’s jurisdiction, and the Court was therefore able to hear the case.⁹

25.7  The second way to bring a case before the Court is under a treaty providing for the submission of a certain class of disputes to the Court when one of the parties so decides; usually these will be disputes relating to the interpretation or application of that treaty. In each case the jurisdiction of the Court depends upon whether the dispute referred to the Court is or is not within the category covered by the treaty. So, for example, in the case brought by the government of Iran against the US in 1992 seeking reparations for attacks by US naval vessels against three Iranian oil platforms, the US argued that the Iranian claims fell outside the obligations in the 1955 Treaty of Amity, Economic Relations and Consular Rights between the US and Iran, which contained a compromissory clause giving jurisdiction to the Court. The dispute as to jurisdiction was settled, as in all such cases, by the decision of the Court, the Court here finding that the dispute between the two States did concern the interpretation and application of the Treaty and that the Court therefore had jurisdiction under the compromissory clause.¹⁰

(p. 528) 25.8  The third way to bring a case before the Court is by use of declarations made under Article 36.2 of the Statute (usually known as the ‘Optional Clause’). Under this provision a State may declare that it recognizes as compulsory, without special agreement, the jurisdiction of the Court in a legal dispute. As between two States, both of which have made a declaration, one of them is entitled to institute proceedings before the Court against the other, and the Court will have jurisdiction so long as the subject-matter of the dispute is covered by the declarations and is not excluded by any reservation. For this purpose, the respondent State is entitled to rely upon any reservation made by the applicant State: the Court’s jurisdiction depends on reciprocity. Thus in the case of Whaling in the Antarctic (Australia v Japan) Japan challenged the jurisdiction of the Court by seeking to rely on the wording of Australia’s reservation regarding the exploitation of certain maritime areas. The case had been brought by Australia against Japan and concerned the interpretation of the International Convention for the Regulation of Whaling. The Court found that the substance of the case fell outside Australia’s reservation and the ICJ therefore had jurisdiction. (Japan failed also on the merits of the case.)¹¹

25.9  The United Kingdom is the only permanent member of the Security Council to have a current declaration under the Optional Clause. Its most recent declaration, made on 30 December 2014, provides an example of some of the kinds of reservations that States make. It reads as follows:

1. 1.  The Government of the United Kingdom of Great Britain and Northern Ireland accept as compulsory ipso facto and without special convention, on condition of reciprocity, the jurisdiction of the International Court of Justice, in conformity with paragraph 2 of Article 36 of the Statute of the Court, until such time as notice may be given to terminate the acceptance, over all disputes arising after 1 January 1984, with regard to situations or facts subsequent to the same date, other than:

   1. (i)  any dispute which the United Kingdom has agreed with the other Party or Parties thereto to settle by some other method of peaceful settlement;

   2. (ii)  any dispute with the government of any other country which is or has been a Member of the Commonwealth;

   3. (iii)  any dispute in respect of which any other Party to the dispute has accepted the compulsory jurisdiction of the International Court of Justice only in relation to or for the purpose of the dispute; or where the acceptance of the Court’s compulsory jurisdiction on behalf of any other Party to the dispute was deposited or ratified less than twelve months prior to the filing of the application bringing the dispute before the Court;

   4. (iv)  any dispute which is substantially the same as a dispute previously submitted to the Court by the same or another Party.

2. 2.  The Government of the United Kingdom also reserve the right at any time, by means of a notification addressed to the Secretary-General of the United (p. 529) Nations, and with effect as from the moment of such notification, either to add to, amend or withdraw any of the foregoing reservations, or any that may hereafter be added.

25.10  In the Aerial Incident case, Pakistan claimed that India was in breach of international law for the shooting down on 10 August 1999 of an unarmed aircraft of the Pakistani navy, resulting in the death of all sixteen on board, who allegedly were on a routine training mission over Pakistani territory. As one of the grounds for the Court’s jurisdiction, Pakistan relied on the declarations made by the two States accepting the Court’s compulsory jurisdiction under the Optional Clause; India however countered that its declaration excluded disputes with any State ‘which is or has been a Member of the Commonwealth of Nations’. Pakistan argued that this reservation lay outside the range of reservations permitted by the Court’s Statute and was obsolete. The Court decided that the limitation on India’s consent to accept the Court’s jurisdiction must prevail, and since Pakistan and India were both members of the Commonwealth, the Optional Clause provided no basis of jurisdiction in this case.¹²

25.11  The Court’s jurisdiction in contentious cases covers only ‘disputes’ between States. What is a ‘dispute’ for this purpose? As indicated in Chapter 24, the Court has adopted the definition of the Permanent Court of International Justice: ‘A dispute is a disagreement over a point of law or fact, a conflict of legal views or interests between two persons.’¹³

25.12  Under Article 94 of the Charter, States are required to comply with the decision of the Court in any case to which they are parties. This will usually involve action by only the government of the State concerned, but if the decision in a case requires action to be taken within a country, the State must ensure that its domestic law will allow it to comply with the judgment. An example where a State was not able to comply with a judgment of the Court, despite its govern-ment’s wish to do so, can be found in the proceedings following the Avena case.¹⁴ The Court had determined that the US should review and reconsider the convictions and sentences of some Mexican nationals as a result of US violation of their obligations to allow consular access to prisoners under the (p. 530) terms of the Vienna Convention on Consular Relations. Although the US administration sought to comply with this decision, the US Supreme Court concluded that the decisions of the International Court of Justice were not directly enforceable in United States courts and that, in effect, the President’s actions to try to give effect to Avena were ineffective under United States constitutional law.¹⁵

25.13  If a party to a case fails to comply with a judgment of the Court, the other party may resort to the Security Council, which may make recommendations or decide upon measures to be taken to give effect to the judgment. Under this provision Nicaragua asked for an emergency meeting of the Council in October 1986 to consider the non-compliance by the US with the judgment of the Court in the Case of the Military and Paramilitary Activities in and against Nicaragua. This case concerned the involvement of the US in the activities of the Contras and other actions against Nicaragua. The United States twice vetoed draft Council resolutions which called for ‘full and immediate compliance’ with the Court’s judgment.

25.14  The existence of the International Court of Justice does not of course limit the right of members of the United Nations to settle their disputes by other means. Indeed, Article 33.1 of the Charter lays down the general principle that:

25.15  The General Assembly or the Security Council may request the Court to give an advisory opinion on any legal question (Article 96 of the Charter). Other organs of the United Nations and, if they are authorized to do so by the General Assembly, its specialized agencies may also request advisory opinions on legal questions within the scope of their activities. No other body, and no State on its own, can ask for an advisory opinion.

25.16  What is a legal question within the meaning of Article 96? The Court has stated that ‘the contingency that there may be factual issues underlying the question posed does not alter its character as a legal question’.¹⁶ Further, the fact that an (p. 531) advisory opinion has been requested on a political issue does not make the question a political rather than a legal one. Indeed, issues surrounding the request and giving of advisory opinions can be intensely political, as can be seen from three recent opinions: Nuclear Weapons, the Wall in the Occupied Palestinian Territory, and Kosovo.¹⁷

25.17  While the Court is not obliged to give an advisory opinion when requested, it has never refused to respond if it has jurisdiction. If there is jurisdiction, the Court will decline to meet a request only for compelling reasons¹⁸ and in order to remain faithful to the requirements of its judicial character.¹⁹ In the Wall opinion the Court was asked, by resolution of the General Assembly, ‘What are the legal consequences arising from the construction of the wall being built by Israel, the occupying Power, in the Occupied Palestinian Territory, including in and around East Jerusalem?’ Some participants in the Court’s proceedings asked the Court to exercise its discretion and refuse to give an opinion for the following reasons: because the request concerned a contentious matter between Israel and Palestine, in respect of which Israel had not consented to the exercise of that jurisdiction; because it could impede a political, negotiated solution to the Israeli–Palestinian conflict; because the Court could not give an opinion on issues which raised questions of fact that could not be elucidated without hearing all parties to the conflict; because an opinion would lack any useful purpose; and because Palestine, given its responsibility for acts of violence against Israel and its population which the wall is aimed at addressing, could not seek from the Court a remedy for a situation resulting from its own wrongdoing. The Court decided that none of these was a ground for it to decline to issue an advisory opinion and it went on to do so.²⁰ It should be noted that the opinion had little effect as regards the continuing actions of the government whom it primarily concerned.

25.18  As the term makes clear, advisory opinions are only advisory and have no binding force. But they are ‘authoritative in the sense that their legal correctness cannot be officially or formally questioned, by the organ to which they are rendered, acting in its corporate capacity’.²¹ If the Court were to indicate that a certain (p. 532) course of action would be definitely illegal or that, of various courses of action proposed only one would be legal, it would be difficult in practice for the organ requesting the opinion not to follow the course advocated by the Court. It is a different matter for States, which are not formally addressed by the opinion. But, since the opinions are given by the principal judicial organ of the United Nations, ‘whatever be their formal authority, their persuasive character and substantive authority must be great’.²² Finally, there is nothing to prevent advisory opinions being given binding force by agreement.²³

25.19  The Court has fifteen judges, no two of whom may be nationals of the same State. The judges are elected by the General Assembly and the Security Council, voting simultaneously but independently of each other. In order to be elected, a candidate must receive an absolute majority of the votes in both bodies. For voting in the Security Council, the permanent members do not have a veto.

25.20  The judges are elected from candidates in a list of persons nominated by ‘the national groups in the Permanent Court of Arbitration’ (Article 4 of the Statute). This means that governments of States do not have the right to propose candidates; that is the role of the four jurists in each State who can be called upon to serve as members of an arbitral tribunal under the Hague Conventions of 1899 and 1907.²⁴ Each group may nominate up to four candidates, not more than two of whom may be of their own nationality.

25.21  The judges must be ‘persons of high moral character, who possess the qualifications required in their respective countries for appointment to the highest judicial offices or are jurisconsults of recognized competence in international law’ (Article 2 of the Statute). It is the intention that in the Court as a whole there should be representation of the main forms of civilization and of the (p. 533) principal legal systems of the world, and as a result, the judges are in practice chosen from the different regional groups of the United Nations as follows: three from Africa, three from Asia, two from Latin America and the Caribbean, five from Western Europe and other States, and two from Eastern Europe. Of these, judges of the nationality of the permanent members of the Security Council have always been included in the Court. Judges are elected for nine-year terms and may be re-elected.²⁵

25.22  Before taking up their duties, the judges make a solemn declaration that they will exercise their powers impartially and conscientiously. A judge cannot be dismissed unless, in the unanimous opinion of the other judges, he or she can no longer fulfil the required conditions. This has never happened. The judges may not exercise any political or administrative function or engage in any other occupation of a professional nature, nor act as agent, counsel, or advocate in any case, nor participate in cases in which, before their election, they have taken part in any capacity. The judges enjoy diplomatic privileges and immunities when engaged on the business of the Court.²⁶

25.23  The Court usually sits as a full court, but it can be formed into chambers. Article 26.1 of the Statute allows the Court to create a chamber to deal with certain categories of cases; under this provision the Court set up a Chamber for Environmental Matters in 1993. It was never used, however, since no State ever asked that a case be dealt with by it, and in 2006 the Court decided not to continue holding elections for the chamber. Under Article 26.2 of the Statute, an ad hoc chamber can be formed to deal with a particular case and this has been done in six cases so far, at the request of the parties. The informal practice is to allow the parties to choose the judges who will sit in the chamber. Each of the chambers has so far comprised five members; in three of the cases the chamber was composed of three ICJ judges and two ad hoc judges chosen by the parties.²⁷

25.24  Article 38, which is one of the most important articles in the whole Statute, states:

1. 1.  The Court, whose function it is to decide in accordance with international law such disputes as are submitted to it, shall apply:

   1. (a)  international conventions, whether general or particular, establishing rules expressly recognized by the contesting States;

   2. (b)  international custom as evidence of a general practice accepted as law;

   3. (c)  the general principles of law recognized by civilized nations;

   4. (d)  subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.

2. 2.  This shall not prejudice the power of the Court to decide a case ex aequo et bono, if the parties agree thereto.

25.25  The sources of law mentioned in subparagraphs (a), (b), and (c) of paragraph 1 above are now generally regarded as the sources of international law which any international tribunal should apply in the absence of an express direction to the contrary. The Court may also decide a case ex aequo et bono (thus without limiting itself to existing rules of international law) if the parties agree; it has not done so yet.

25.26  Since a decision of the Court has no binding force except between the parties and in respect of that particular case, the Court is, in strict law, not bound even by its own precedents, let alone by the decisions of other international tribunals. In practice, however, the Court attaches great weight to previous decisions, not only its own and those of the Permanent Court of International Justice, but also on occasions those of arbitral tribunals of high standing.

25.27  Contentious cases are begun by filing with the Court either an application, or the compromis or special agreement, where one exists. The application is signed by the agent or some other duly authorized person. As agent it is usual to appoint a legal adviser to the foreign ministry or a diplomatic representative in The Hague. The agent, who acts as the link between the Court and the applicant State, is responsible generally and at all stages for the handling of the case. In (p. 535) drawing up pleadings and presenting argument orally the agent is generally assisted by Counsel, including in some cases law officers, and international law academics. An application must identify the parties, the basis of the Court’s jurisdiction, the nature of the dispute, and the precise nature of the claim. It must summarize the main facts and grounds on which the claim is based. These are developed in detail in the Memorial, to which documentary evidence is attached.²⁸

25.28  The official languages of the Court are French and English, although there is nothing to prevent a party using another language provided it arranges for a translation to be made into one or other of the official languages. The procedure consists of two parts: written and oral, and the oral proceedings may include the hearing of the evidence of witnesses. The hearing is public, unless the Court decides otherwise, or unless the parties demand that the public are not admitted.

25.29  Sometimes a State has chosen not to appear before the Court. Nevertheless, the Court will decide on its jurisdiction and on the merits of the case. For example, Iran did not appear in a case brought to the Court by the US after some of its embassy staff had been taken hostage and its diplomatic premises taken over.²⁹ The Court proceeded to decide the case, establishing the facts by reference to material provided by the US and from public sources.

25.30  If a case is brought before the Court by the application of one party alone, the other party may object to the jurisdiction of the Court or to the admissibility of the case, provided that is done before the expiry of the time-limit fixed for the delivery of the first pleading. This will cause the proceedings on the merits to be suspended while the Court hears the objection. It is for the Court itself to judge whether the objection is valid. Three possibilities are open to the Court: to uphold the objection, to overrule it, or to join it to the merits of the case to be heard at the same time.³⁰

25.31  Objections to jurisdiction have already been discussed. Admissibility is a concept separate from that of jurisdiction and goes to the nature of a case. If, for example, the applicant’s claim is found to concern a dispute which has disappeared or if a case is found to be moot, academic, or devoid of object and purpose, then the Court will declare the case inadmissible and decline to (p. 536) adjudicate upon its merits.³¹ The reason is to safeguard the judicial function of the Court. A case can become moot after the filing of the application, for example as a result of a change of practice or the giving of undertakings on the part of the respondent.³²

25.32  The deliberations of the Court take place in private and remain secret. All questions are to be decided by a majority of the judges present, and in the event of an equality of votes, the President or the judge who acts in his place has a casting vote. The judgment states the reasons on which it is based and any judge may deliver a separate opinion, which may be either a ‘dissenting opinion’, or an ‘individual opinion’ agreeing with the conclusions of the judgment, though not necessarily with the reasons on which it is based. The judgment is final and without appeal. The Court may, however, be asked to interpret it if a dispute arises as to its meaning or scope³³ or even to revise it in the event of a new decisive fact being discovered.

25.33  A State which considers that it has an interest of a legal nature which may be affected by the decision in the case may ask the Court to be permitted to intervene. Such requests are rare. However, third parties have an automatic right to intervene whenever the Court has to decide on the interpretation of a treaty to which they are party. If they exercise this right, they are bound by the judgment. Usually each party has to bear its own costs; having regard to the fees charged by counsel and the expenses necessary in obtaining evidence, those costs can be substantial. For States to whom the cost of taking a dispute to the Court would be prohibitive, a trust fund has been created to provide financial assistance in certain circumstances. Funds are provided only in cases where the jurisdiction of the Court is not in doubt.³⁴ The costs of the Court itself are met not by the parties (as is the case with arbitrations) but from the UN budget.

25.34  If the Court already includes judges of the nationality of both the parties, these judges retain their right to sit in the case. If the Court includes a judge of the nationality of one of the parties only, the other party has the right to choose a judge for that particular case, who will usually, but not always, be of that party’s nationality. If the Court does not include a judge of the nationality of either of the parties, both parties have the right to choose a judge for the case.

(p. 537) 25.35  The procedure for applications for advisory opinions is a little different. The Court may hold written and oral proceedings. States and international organizations will be asked to give information on the question before the Court, in particular the States Members of the organization which has requested the opinion. Those States are not in the same position as parties to contentious proceedings. Any State not consulted by the Court may ask to take part. Participants may submit written statements, and States are then usually invited to present oral statements at public hearings. Palestine was invited to (and did) participate in the proceedings relating to the Wall opinion and the ‘Provisional Institutions of Self-Government of Kosovo’ were invited to (and did) participate in the proceedings for the advisory opinion which concerned the declaration of independence.³⁵

25.36  The Court may order provisional or interim measures ‘which ought to be taken to preserve the respective rights of either party’ (Article 41 of the Statute).³⁶ In some cases, the Court has ordered both parties to refrain from taking any action ‘which might aggravate or extend the dispute … or prejudice … rights … in respect of the carrying out of whatever decision the Court may render in the case’.³⁷ If the rights are such that any breach of them eventually found could be repaired (for example, by the payment of compensation), or if the parties have already accepted obligations to refrain from actions which would aggravate the dispute (for example, through the Security Council), the Court will not order provisional measures.³⁸

(p. 538) 25.37  Under Article 66 of the Rules of Court, requests for such measures will be treated as a matter of urgency; if the Court is not sitting, the judges will be convened by the President forthwith. The Court has power to indicate provisional measures where it prima facie has jurisdiction; where there is no basis on which jurisdiction can be founded, it will not issue such measures, as in the Case concerning Legality of Use of Force (Yugoslavia v Belgium), one of the cases brought by the Federal Republic of Yugoslavia against NATO States in relation to the bombing of the FRY in 1999.³⁹ The Court is entitled to indicate measures other than those proposed in the request and even to indicate measures proprio motu (i.e. without any request having been made).

25.38  It was once a controversial question whether the measures indicated by the Court are legally binding or not. The words ‘indicate’ and ‘suggested’ in Article 41 may give the impression that the measures are not intended to be binding, but the Court has decided that provisional measures do have a binding effect. In a case brought by Germany against the US in relation to the rights under the Vienna Convention on Consular Relations of two German brothers sentenced to death in US courts, the Court ordered that the US should take ‘all measures at its disposal’ to ensure that the remaining brother was not executed prior to the Court’s judgment in the case. The US government transmitted the order to the Governor of Arizona, who did not give effect to it and the German national was executed. The Court found that the US had failed to take the measures at its disposal to prevent the execution before the Court had disposed of the case and the US was accordingly in breach of its obligation under the order for provisional measures.⁴⁰