In order to conceptualize, describe, and explain the effect of Europeanization on the domestic institutions of the member states, most studies draw on two major strands of theory. They either embrace some sort of resource-dependency approach, which conceives of the European system of governance as a new political opportunity structure that changes the distribution of power resources among domestic actors. Or they resort to organizational theories of institutional change, which understand the domestic impact of Europe as a process of institutional adaptation in which domestic actors adopt and internalize new rules and practices. I argue that the two approaches are embedded in different forms of institutionalism and therefore vary in their expectations of whether, when, and how Europeanization effects the institutions of the member states.

The following two sections discuss resource dependency and institutional adaptation with respect to their capacity for explaining the domestic impact of Europe. Rather than embarking on an ideal-type metatheoretical discussion of different institutionalisms, I contrast the two approaches according to:

• the major propositions which resource dependency and institutional adaptation pose on how actors behave, how institutions affect actors' behavior, and why institutions change;

• the expectations which the two approaches generate about the conditions, the process, the degree, and the outcome of domestic institutional change caused by Europeanization.

The domestic impact of Europe as a resource-dependent process

Resource-dependency approaches are usually based on some sort of rational choice institutionalism as defined by James March and Johan Olsen (March and Olsen 1995: Chapter 2) and Peter Hall and Rosemary Taylor (Hall and Taylor 1996).