[From the introduction]. On January 1st, 2007 the accession of Bulgaria and Romania completed the enlargement of the European Union (EU) to ten Central and Eastern European (CEE) states. The same countries have also become NATO members. Other former Communist states, however, are far from sharing this privileged position. While the Western Balkans might, sometime in the future, join EU, chances are slim for Commonwealth of Independent States (CIS) republics. European Union's present Eastern border will probably remain unchanged for a very long time. The reasons of this division are explored in the following sections with an emphasis on the close association between democratization and EU accession. Unlike most research in the field, however, the analysis combines an International Relations institutionalist approach and transitology. Section 2 uses Freedom House evaluation of political rights and civil liberties to illustrate the completely different degrees of democratization of states within and outside EU's enlargement process. Section 3 builds an International Relations explanation of the post-Communist democratization process based on Alexander Wendt's constructivism. Section 4 adds transitology elements to explain the regional success or failure of democratization mechanisms. The Conclusion summarizes this paper's main findings and evaluates the perspectives of further EU enlargement
