Equality of States and Mutual Membership in European Union Law: Contemporary Reflections

In line with the solutions adopted in other instruments establishing international organizations, Article 4(2) TEU incorporates the doctrine of equality of States into the EU legal order. But the doctrine of equality of States is not the only factor inspiring the Treaty provision. It is generally accepted that the wording of Article 4(2), echoing the definition of formal equality which is contained in the core international human rights instruments—as well as in the constitutions of States—, is also a clear expression of the strict nexus between States and individuals under EU law. Unsurprisingly, the respect of the equality of Member States is also intimately tied to the protection of fundamental values upon which the Union is based—starting from the respect of the rule of law—and thus contributes to the affirmation of the autonomy of EU law, as well as to the establishment of an idea of “mutual membership within the Union”, that is, the idea that unilateral actions of Member States are likely to have an influence on their mutual relations, even in situations where the linkage with EU law is less strict. Against this background, this chapter explores some recent elements of practice attributable to Member States of the Union, showing a growing recourse to a logic of unilateralism, with a view to assessing their implications for a proper enforcement of the equality principle. To do so, the chapter is structured into four sections. After a global assessment of the equality principle in EU law (Sect. 3.1), Sect. 3.2 looks at recent episodes of unilateral infringements of EU law put in place by some EU countries, justified by the need to protect national prerogatives, and creating tensions in terms of equality among Member States before the Treaties. Section 3.3 considers the judicial unilateralism showed recently by the supreme courts of some Member States in re-shaping the interplay between EU law and municipal law, and the influence of such unilateralism on the affirmation of the equality principle. Section 3.4 concludes the chapter, summarizing its main findings.