By Marcus How in Vienna 2004 was among the most consequential years in the history of the European Union, as the number of its member states nearly doubled. In the space of a decade, those new EU states within Central and Eastern Europe (EU-CEE) had succeeded in aligning their formerly communist institutions with minimum EU standards. This had profound implications not only for the new member states themselves, but also for the bloc as a whole – and decisionmaking within it. Twenty years on, with Romania, Bulgaria and Croatia having acceded to EU membership in the interim, the further integrat…