This panel is composed of 5 papers. They all focus on issues related to regional parliaments in the EU post Lisbon. The Lisbon Treaty of December 2009 implemented a series of subsidiarity reforms which have given regional parliaments new opportunities for greater involvement in EU affairs. The first paper seeks to explore the implementation of the Early Warning System (EWS) in terms of regional parliamentary activity within the EWS and patterns accounting for such activity across a sub-set of European regions (Bauer, Boronska & Tatham). Thanks to three qualitative cases studies, the second paper focuses on the inter-parliamentary activities of regional parliaments as triggered by their involvement in EU affairs (Eppler). The third paper analyses another type of inter-parliamentary interaction: that between regional and national parliaments in their subsidiarity monitoring work (Högenauer). Shifting the focus from inter-parliamentary relations to executive-legislative relations, the fourth paper seeks to explore the extent to which the EWS has affected those at the regional level (Fleischer). On the basis of these developments, the last paper re-assesses the thesis of a ‘Europe of the Regions’ by surveying recent intra-, supra- and inter-state changes (Müller). This corpus of research is then discussed by an international expert on territorial politics and the involvement of regions in EU affairs (Bursens).