European Union Enlargement Policy
Enlargement has always been an essential part of the European integration project. However, it was the expansion of the European Union (EU) to include the ten Central and Eastern European Countries (CEECs), Cyprus and Malta, unprecedented in scope and scale, which presented the Union with an opportunity to develop a multifaceted set of instruments and transformed enlargement into one of EU’s most successful policies. The numerous challenges of the accession process, along with the enormity of the historical mission to unify Europe, lent speed to the emergence of the study of EU enlargement as a key research area.
The majority of the early studies investigated the puzzle of the EU’s decision to enlarge with the CEECs, and the costs and benefits of the Eastern expansion. However, the questions about the impact of EU enlargement policy inspired a new research agenda. Studies of the influence of the EU on candidate and potential candidate countries have not only widened the research focus of Europeanization studies (beyond the member states of the Union), but also stimulated and shaped the debates on the scope and effectiveness of EU conditionality.
Conditionality has become a useful concept for analyzing the impact of the EU on domestic politics in enlargement countries. Numerous studies have demonstrated the significance of a credible membership perspective and the clarity of the membership conditions for the success of the EU’s transformative power. Following the completion of the fifth enlargement, the effectiveness of the EU approach towards the Western Balkans and Turkey, as well as the sustainability of the Union’s impact in Central and Eastern Europe and the limitations of post-accession conditionality have attracted a lot of scholarly attention. Research on EU enlargement policy has also shaped the debates on the performance of the European Neighbourhood Policy and the diffusion of the EU’s impact beyond enlargement and neighbouring countries.