Special Issue: Security Cooperation beyond the Nation State: The EU's Common Security and Defence Policy

The Europeanisation of candidate countries and new members is a rather recent research area that has grown strongly since the early 2000s. Research in this area has developed primarily in the context of the EU's eastern enlargement. A small number of theoretically informed book-length studies of the EU's influence on the Central and Eastern European candidate countries have provided a generalisable conceptual framework for this research area, drawing on the debate between rationalist institutionalist and constructivist institutionalist approaches in International Relations and Comparative Politics. This framework makes these studies highly compatible with analyses of the Europeanisation of member states, with which they also share one key empirical finding, namely that the impact of the EU on candidate countries is differential across countries and issue areas. At the same time, the theoretical implications of these findings appear more clear-cut than in the case of the Europeanisation of member states: rationalist institutionalism, with its focus on the external incentives underpinning EU conditionality and the material costs incurred by domestic veto players, appears well-suited to explaining variation in the patterns of Europeanisation in candidate countries. A very recent development within this research agenda is the focus on the Europeanisation of new member states. While the study of the EU's impact during the early years of membership was hitherto primarily a subfield of analyses of the Europeanisation of member states, it has now become an extension of studies of candidate countries by analysing the impact of accession on the dynamics of pre-accession Europeanisation and how durable and distinctive the patterns of candidate Europeanisation are in the post-accession stage.