There is growing sentiment that the rise of illiberal democracy in Central and Eastern Europe poses a serious threat to fundamental European values. Within the framework of the European Union (EU) legal system, how do post-socialist member states actually comply with fundamental European values? While there are multiple contradictory theories about the success or failure of assimilation in the region, there is surprisingly little datadriven literature which directly compares post-socialist member state compliance to the rest of the European member states. This paper fills the gap by comparing post-socialist compliance patterns with the rest of the EU, using data on infringement cases opened by the Commission. It finds that post-socialist member states are generally assimilating into pre-existing patterns of European compliance. However, they are demonstrably worse in fundamental European values compliance-and though a legal basis for enforcing these values exists, the EU currently lacks the practical ability to do so.