The issue of European citizenship has been subject to a heated debate in legal studies as well as in social sciences. The debate has covered several aspects. Originally, it began with the controversy of whether citizenship beyond the nation-state is possible at all.1 Afterwards, some scholars focused on the limitations of European citizenship in comparison to national citizenship bemoaning the underdeveloped character of European citizenship,2 whereas others highlighted the constructive potential of European citizenship for the future, grounding it in citizenship practice.3 The constructive potential of European citizenship was discussed particularly with respect to the concept of constitutionalism against the background of the European constitutionalization process4 and additionally as a specific form of social citizenship of the European Union.5 Moreover, the debate on European citizenship has spawned a sub-debate on the very concept of European citizenship. It has proceeded on three tracks. The first track covered the rather abstract issue of optimal citizenship for the EU as well as the instrumental function of citizenship, both analyzed from the perspective of political economy.6 The second track related to the issue of whether European citizenship is a mere derivative of the member states’ citizenship. In this vein, some authors postulated extending European citizenship to cover European denizens (citizens of non-EU countries with residence in an EU member state), thus dislodging European citizenship from the national, which would make European citizenship an independent and recognizable construction. The third track referred to the controversy of whether citizenship indicates only legally institutionalized categories of rights and obligations or if it is also based on shared values and objectives.7 Recently, the rejection of the draft constitutional treaty has led to a critical assessment of European citizenship.8