Within the European Union identity or separatist trends are observed in the frame of Nation-states members, for instance in Catalonia, Flanders, Scotland, Northern Italy, Corsica or the Basque country. By claiming national aspirations that often go beyond the only recognition of a cultural, economical or regional personality within their origin state, these trends are to be distinguished from “regionalism” and can thus be qualified as regional nationalisms. Not only their claim for autonomy can sometimes question the legitimacy of the state on which they depend, as today’s incapacity of Belgian institutions to address the autonomy willingness of the Flemings shows it, but also because their claim reference is that of the Nation-State. Regional nationalisms question in fact the potential splitting up of the European political space and the risks of dilution and breaking up of old European states into small state entities with limited economical viability seen as a factor of instability.