ABSTRACT
Although enlargement increases the preference diversity in the European Union (EU), this paper shows that enlargement has not led to a deterioration of compliance with EU law. In three of the EU's four enlargement rounds, the new member states comply better with EU law than the old member states. The Southern enlargement in the 1980s is the only one that led to a substantial increase in non-compliance. Particularly surprising for the main compliance theories, which focus on state power, adjustment costs, administrative capacities or legitimacy, is the good performance of the postcommunist Central and Eastern European new member states after the Eastern enlargement in the 2000s. Our analysis suggests that the use of preaccession conditionality in the Eastern enlargement explains why these new members perform so well – unlike their Southern counterparts who faced equally unfavourable country-level conditions for compliance.
