La cittadinanza «sostanziale» dell’UE alla luce della proposta del gruppo di Heidelberg: verso una «Reverse Solange»?

This paper presents an analysis of the issue of the European citizenship in light of the interpretative key proposed by a group of scholars from the Max Planck Institute for Comparative Public Law and International Law of Heidelberg and based on the Zambrano doctrine, a leading case in this field. Their proposal revolves around the protection of fundamental rights through the path of European citizenship. The goal of the paper is to offer some insights on a concept which has been analyzed in relation to the freedom of movement. Our analysis starts from a ‘multidisciplinary’ understanding of citizenship, that connects the different levels and the different spheres in which the rights and obligations connected with it develop. We shall focus, therefore, on the «Citizenship in the EU context» rather than on the EU citizenship. The paper raises a question: does citizenship remain an exclusive scope of the ‘thinner’ state sovereignty –understood as part of the «national identity» that the Union has to respect (Art. 4.2 TEU) – or is it a central element of what we could define as a «composite national identity»?