The relationship between EU law and national constitutional law, including constitutional law in federalism matters, has been subject to an ongoing scholarly debate. This monograph contributes to this debate in two ways. The author argues for an approach to constitutional law that goes beyond the classic - coined dogmatic - understanding of constitutional case law regarding federalism as expounded in Belgian academia. Building on that basis, he sets out to rethink the framework within which the connection between EU law and national constitutional law can be understood. The analysis delves into the relationship (and sometimes tension) between ‘rule-of-law' values (which may serve as checks upon instrumental forms of reasoning) and the toolbox deployed in constitutional court case law to accommodate several rather pragmatic needs.