Fundamental part and constitutional core of the EU Treaties: On the legitimacy of the ECJ’s new constitutionalism

Provisions of the TEU with a concise constitutional content have gained weight in the case law of the ECJ. The article conceptualizes this weight as substantive precedence, which has an interpretation-guiding function for Union primary law, and shows that the new constitutionalism of the ECJ is supported by the intention of the treaty authors. The Lisbon Treaty has consolidated the previously heterogeneous primary law of the Union under constitutional law, equipped it with basic provisions and provided it with a constitutional core, which suggests a principle-oriented interpretation in the sense of substantive primacy. It therefore falls short of the mark to understand and evaluate the growing importance of Art. 2 TEU solely in terms of guaranteeing rule of law structures in the Member States.