competitive testing, in which competing theories are pitted against each other in explaining a single event or class of events;
a ‘domain of application’ approach, in which each theory is considered to explain some sub-set of empirical reality, so that, for example, utility-maximizing and strategic bargaining obtain in certain circumstances, while socialization and collective preference formation obtain in others;
a ‘sequencing’ approach, in which one theory may help explain a particular step in a sequence of actions (e. g. a constructivist explanation of national preferences) while another theory might best explain subsequent developments (e. g. a rationalist explanation of subsequent bargaining among the actors); and
‘incorporation’ or ‘subsumption’, in which one theory claims to subsume the other so that, for example, rational choice becomes a sub-set of human behaviour ultimately explicable in terms of the social construction of modern rationality.
Looking at the substantive empirical work in their special issue, Jupille, Caporaso and Checkel (2003) find that most contributions to the rationalist/constructivist debate utilize competitive testing, while only a few (see, for example, Schimmelfennig 2003a) have adopted domain of application, sequencing, or subsumption approaches.
Nevertheless, they see substantial progress in the debate, in which both sides generally accept a common standard of empirical testing as the criterion for useful theorizing about EU politics.
European integration theory is far more complex than it was in 1977 when the first edition of this volume was published. In place of the traditional neo-functionalist/ intergovernmentalist debate, the 1990s witnessed the emergence of a new dichotomy in EU studies, pitting rationalist scholars against constructivists. During the late 1990s, it appeared that this debate might well turn into a metatheoretical dialogue of the deaf, with rationalists dismissing constructivists as ‘soft’, and constructivists denouncing rationalists for their obsessive commitment to parsimony and formal models. The past several years, however, have witnessed the emergence of a more productive dialogue between the two approaches, and a steady stream of empirical studies allowing us to adjudicate between the competing claims of the two approaches.
Furthermore, whereas the neo-functionalist/intergovernmentalist debate was limited almost exclusively to the study of European integration,3 the contemporary rationalist/ constructivist debate in EU studies mirrors larger debates among those same schools in the broader field of international relations theory. Indeed, not only are EU studies relevant to the wider study of international relations, they are in many ways the vanguard of international relations theory, insofar as the EU serves as a laboratory for broader processes such as globalization, institutionalization, and socialization.
Despite these substantial measures of progress, however, the literature on European integration has not produced any consensus on the likely future direction of the integration process. At the risk of overgeneralizing, more optimistic theorists tend to be drawn from the ranks of neo-functionalists and constructivists, who point to the potential for further integration, the former through functional and political spillovers, and the latter through gradual changes in both йlite and mass identities and preferences as a result of prolonged and productive cooperation. In empirical terms, these analysts frequently point to the rapid development of new institutions and policies in the second and third pillars, and the increasing use of the so-called ‘open method of coordination’ (OMC) to address issues that had been beyond the scope of EU competence. Rationalist and intergovernmentalist critics, on the other hand, tend to be sceptical regarding claims of both spill-over and socialization, pointing to the poor record of Commission entrepreneurship over the past decade and the sparse evidence for socialization of national officials into European preferences or identities, noting that the Commission has proven to be a poor stimulator of political spill-over in recent years. For these scholars, the EU may well represent an ‘equilibrium polity’, one in which functional pressures for further integration are essentially spent, and in which the current level of institutional and policy integration is unlikely to change substantially for the foreseeable future (Moravcsik 2001: 163).