[From the introduction]. Enlargement is often called the most successful foreign policy of the European Union (EU). The attractiveness of EU membership and the strict conditionality attached to the accession process have vested the EU with considerable transformative power in the applicant countries (Grabbe 2005; Schimmelfennig and Sedelmeier 2005). After the breakdown of Soviet communism and hegemony in Eastern Europe, enlargement has been credited with having contributed significantly to economic recovery, peace and stability as well as democratization in the transition countries of the region. With the accession of Bulgaria and Romania in January 2007, the Fifth Enlargement of the EU has been completed. Whereas the Western Balkans and Turkey continue to have a membership perspective, the EU has devised the European Neighborhood Policy (ENP) for the remaining countries of Eastern Europe and the Mediterranean as an alternative to accession. It remains to be seen, however, whether ENP will be able to produce similarly positive effects as enlargement. This policy question provides the practical interest we have in this paper....In this paper, we address these potential sources of bias and uncertainty. On the one hand, we systematically include in our analysis core variables of modernization theory as well as several proxies for diffuse international and transnational influences beyond the specific incentives of the EU. Second, we extend the study to 36 countries of the “European neighborhood” and thus to almost all post-communist and Mediterranean countries from the late 1980s to the beginning of the 21st century. Finally, in order to deal with this expanded data set, we move from comparative case studies to a panel regression analysis
