Fundamental part and constitutional core of the European Treaties. On the legitimacy of the new constitutionalism of the CJEU

Since the entry into force of the Lisbon Treaty, the Court of Justice of the European Union (CJEU) has detailed its interpretation, in a constitutional sense, of the Treaties. In several decisions, it has developed a new axiological conception of the constitution, one that complements, or even surpasses, the established functionalist (effet utile) conception. The new constitutionalism in the CJEU’s case law may be found initially in a case law trend that reinforces the autonomy of Union law with respect to the sphere of action of international treaties. In a further stage of development, the CJEU asserted the constitutional substance of the Treaties against the authoritarian practices of several EU member states. A clear example of this is the plenary decision of 16 February 2022 on the European Rule of Law Mechanism. Prominent voices in scholarship see this case law as problematic judicial activism. According to this critical view, which is mainly fueled by concern for the autonomy of member states, the ‘values case law’ of the CJEU lacks functional legitimacy and a rational methodological framing. This article aims to show instead that such a development is supported by the intention of the authors of the Treaty, as was indeed expressed in the reorganization by the Lisbon Treaty. In 2009, this Treaty effected a consolidation of the previously heterogeneous primary law of the Union within the framework of constitutional law (Art. 1, par. 3, TEU), endowed it with fundamental provisions (Arts. 1 to 19 TEU) and provided it with a constitutional core (Arts. 1, 2 and 3, par. 1, TEU). This suggests, or perhaps even requires, a principle-oriented interpretation such as to confer substantive primacy to some provisions over others.