The paper will argue that a combination of sociological institutionalism with theories of social learning is better suited to explain the varieties of the impact of European regional policy than generalization based on historical and rationalists intuitionalist approaches. It will distinguish three modes of interaction between the European and the domestic arena: policy learning, policy experimentation and policy conflict. European regional policy encompasses the two areas of structural funds and state aid control, and follows the paradigm of "endogenous development," the principles of partnership and competitiveness and a certain set of procedures. Whilst in Southern Italy policy learning took place with regard to both European policy areas, in Eastern Germany structural funds induced a process of policy experimentation, but state aid control led to intense policy conflict between all the actors in Germany and the European Commission
