The International Court of Justice and the Court of Justice of the European Union: Between Fragmentation and Universality of International Law

Abstract

This chapter discusses how the Court of Justice of the European Union (CJEU) has used judgments of the International Court of Justice (ICJ) in its legal reasoning. The CJEU uses ICJ jurisprudence in three main ways: when discussing customary international law, when applying the law of treaties, and when using international law to interpret and develop principles of EU law. The chapter reviews the cases in which the CJEU and the Advocates General have discussed ICJ cases, including areas of international humanitarian law, diplomatic and consular law, nationality and citizenship, the law of the sea, and the international law of treaties. On the one hand, the CJEU's use of ICJ case law may show its commitment to the universality and coherence of international law. However, the CJEU also has a strong commitment to the coherence and unity of EU law, and has emphasised the autonomy of the EU legal order. The chapter shows that, upon closer inspection, the CJEU interprets and applies ICJ jurisprudence through an EU law prism. It also shows that, over time, principles of international law are transformed into principles of EU law. In these instances, the CJEU no longer refers to ICJ/PCIJ jurisprudence, but as autonomous EU law principles. ICJ jurisprudence is used to fill gaps, or to support certain legal arguments, but it is not followed as if it were a hierarchically superior court.

International Law and the European Union

“…Yet the CJEU has not shown much interest in the unity of international law, and is more focused on preserving the autonomy of the EU legal order. 82 Much of this debate has focused on the issue of conflict between legal orders. There is a tendency to focus on courts, and the 'clashes' that occur, especially in high-profile judgments.…”

EU External Relations and International Law: Divergence on Questions of ‘Territory’?

“…At least as far as enforcement is concerned, in international law, state jurisdiction is traditionally quite closely linked to territorial notions, and it has also been discussed by both the CJEU and the International Court of Justice (ICJ) as such. 38 In fact, jurisdiction can be seen as the exclusive competence of states to set and enforce the rules on its territory. 39 It is well-known that part of these jurisdictional competences has been transferred to the EU, both where the creation and the enforcement of norms is involved.…”