A Game-Theoretical Approach to the Accession of Central and Eastern European countries to the European Union in 2004 and 2007

This paper employs a novel approach in applying the cheap talk signalling game to study the EU accession game of the 10 Central and Eastern European states that joined the European Union in 2004 and 2007. The interdisciplinary application of a Bayesian game to international relations reveals the strategic interactions between the Union and applicant states in the light of the Copenhagen criteria and the unprecedented challenges countries faced during the post-Communist transition since 1989. The paper first presents the historical background about the EU accession process, debates on EU conditionality and existing game-theoretical approaches, before presenting the timeline and data on accession and reform speed of applicant states from 1989 to 2007. The model applies a signalling game to the negotiations process where the European Commission’s annual progress reports are seen as costless, unverifiable and observable signals to the applicant states about their final EU accession speed. It is demonstrated that possible equilibria outcomes can be uninformative or informative, depending on the players’ divergence of interests with regards to reform speed. Furthermore, the model is used to explain the outcomes seen in three ex-post case studies, taking into account additional domestic and external factors that shaped the varying outcomes of accession and reform speeds in the two EU enlargement waves in the 2000s.