SepaRope is the first empirically-grounded and comparative project rethinking the theory and practices of Separation of powers in present-day European Union. It addresses the very core of ‘democratic governance in a turbulent age’ and connects to all themes of the call. Separation of powers, the classic model of decision-making, entrusts different state functions to different branches (legislative, executive, judiciary) and serves the double purpose of ensuring collective will-formation and control of those in power. The polyarchic multilevel nature of the EU is not easily reconciled with the separation-of-powers-model, either at EU or national level. SepaRope demonstrates in combined horizontal and vertical inquiries how recent economic and political developments affect the EU’s institutional framework and the anchoring of EU decision-making in national legitimacy. It combines conceptual constitutional analysis with empirical research in three fields (Economic and Monetary Union, migration, trade), in which EU decision-making is controversial, rights-sensitive and illustrative of recent power shifts. Working package 1 develops a joint conceptual framework for identifying and examining will-formation and control structures. WP2-4 conduct autonomous but interlinked empirical and legal-analytical studies of the three branches in the three policy fields, respectively, exposing ever-increasing ‘grey areas’ of diffuse, ring-fenced, and informalised public power. WP2-4 demonstrate the three branches’ mutually constitutive nature and contingency of power shifts. WP5 makes concrete innovative and practically viable suggestions to EU and national institutional actors on how will-formation and control structures can be strengthened in the polyarchic multilevel EU. Stakeholders are involved as interviewees and participants.