In view of the discussion, at this conference, of comparisons between the European Union and the United States, I should like to emphasize that there are great similarities, but also profound differences, between the two systems. These similarities, and some of the differences, will be illustrated by examples that I shall give, but it is useful to emphasize certain points at the outset.
In the first place, the European Union (EU) is not a federal system, and the European Court of justice (ECJ) is not a federal supreme court. However, the EU resembles a federal system in that it is based on a division of powers between the Union and the Member States. In instituting that division of powers, and in endowing the European Communities (later the EU) with certain legislative, executive, and judicial institutions, the founding treaties' bear some resemblance to an incipient federal constitution. However, they could also be regarded (perhaps more accurately) as an organization of states in which certain limited powers, mainly in the economic field, were conferred on common institutions in the expectation of increasing integration (hence the reference, in the preamble to the European Economic Community Treaty, to "an ever closer union").
Second, the founding treaties contained few explicit constitutional principles. The main principles were developed by the ECJ itself: most importantly, the principles of primacy of Community law and the principle of direct effect as well as some fundamental "general principles of law." The principle of primacy may suggest an analogy with a federal system but has an obvious independent justification in the EU: it would simply make no sense to have an EU in which the laws of the Member States could prevail over the laws of the Union. But this is one area where, as I shall suggest, judicial dialogue has been particularly important in delineating the principle and in securing its recognition.
Third, judicial dialogue is a vital feature of the ECJ because of the unusual character of its jurisdiction. In contrast to the U.S. Supreme Court, and perhaps to supreme courts generally, the ECJ is not essentially an appellate court. It has had, since 1989, when the Court of First Instance was set up, jurisdiction to hear appeals from that Court. But that is not its main function, or its main caseload. It has two main heads of jurisdiction. First, there is an original jurisdiction to hear cases between Member States and Union Institutions (primarily the European Parliament, the Council of the Union, and the European Commission); in that respect, its cases are sometimes of an explicitly constitutional character, for example, on the division of powers between the Union and its Member States. second, it has jurisdiction to rule on many, although not all, questions of Union law referred to it by the "national courts"-i.e., the courts of the Member States, where a national court considers, in a case it is hearing, that a decision on the question is necessary to enable it to give judgment.
Under this procedure-by which any court or tribunal of a Member State may, and a final court must, refer such a question to the ECJ for a "preliminary ruling" before it gives judgment-there is a sharing of jurisdiction between the national court and the ECJ which entails a special form of "judicial dialogue."
Moreover, such preliminary rulings, given by the ECJ on references by national courts, have not only been quantitatively the most significant part of the ECJ's caseload; they have also been the means by which the ECJ has fashioned-with the help of this judicial dialogue-many of the most important principles of the EU's constitutional and legal system.
It may, therefore, be appropriate to look briefly at judicial dialogue and the cross-fertilization of legal systems within the EU, before turning to the external dimension.
II. JUDICIAL DIALOGUE AND THE CROSS-FERTILIZATION OF LEGAL SYSTEMS: THE EUROPEAN UNION
Although the Treaties provide a broad legal framework, and the Union legislature has enacted a vast body of generally very detailed legislation (at the end of 2002, apparently some 97,000 pages of the Official Journal). …