Whatever terminology one might wish to employ to describe the form of integration constituted by the European Union and its Member States, one fundamental attribute of that arrangement has always been the division, as between the Union and its Member States, of competence to conclude international agreements with other subjects of international law. Today, the fact that treaty-making competence—as an external facet of the more general division of legal authority—is divided and, to some extent, shared between the Union and its Member States is reflected by some of the opening provisions of the Treaty on European Union and the Treaty on the Functioning of the European Union. Notwithstanding the changes to the scope and nature of the powers conferred upon the Union, resulting from both changes to primary law and the evolution of the case law of the Court of Justice of the European Union (CJEU), the basic characteristics of the conferment as an attribution of a limited kind has always been the same; there has always existed a polity endowed with a treaty-making authority divided between and, indeed, shared by, the Union and its Member States. In the early 1960s mixed agreements—that is, agreements to which the European Union
THE STATUS OF INTERNATIONAL AGREEMENTS CONCLUDED BY THE EUROPEAN UNION IN THE EU LEGAL ORDER