What shapes they dynamics and trajectories of EU integration? While the question is as old as the European integration project, new answers are abound: ‘New intergovernmentalists’ re-discover the dominance of governments at the expense of supranational actors; the principle of ‘ever closer union’ has had to give way to differentiated integration; and mass publics put constraints on what kind of European policies elites can negotiate in Brussels and at home. Philipp Genschel and Markus Jachtenfuchs argue that these developments reflect a common cause: the integration of core state powers, by which they mean “the increasing involvement of EU institutions in key functions of sovereign government including money and fiscal affairs, defence and foreign policy, migration, citizenship and internal security.” Read their recent article “More integration, less federation: the European integration of core state powers” to understand how the integration of core state powers has not consolidated a nascent European federation, but instead fuelled the EU’s fragmentation.