This paper examines European Union (EU) causal mechanisms and policy instruments triggering change within domestic systems throughout the lenses of the Europeanization approach. Instead of looking at the process of European Integration from its formal/legalistic components, we use theoretical public policy analysis to explore the arenas and the causal mechanisms that structure the encounters between the EU and domestic systems of governance. Policy instruments are related to policy arenas and in turn to different mechanisms of transmission thus originating a typology of European Policy Modes. The overall ambition is to revitalise the literature on modes (or arenas) of policy, thus those scholarships assuming that the structuring of politics depends on the type of confrontation and strategic interaction producing around specific policy issues.