The Member States of the European Union are undoubtedly sovereign. However, their constitutions cannot be understood without taking into consideration their interaction with the constitutional order of the European Union. Europe is thus in a state of constitutional plurality: The constitutions of the Member States and the European Union co-exists and overlap. Some authors have even derived a normative argument from this: No hierarchy needs to exist between these constitutions but rather constitutional pluralism prevails. This study assesses such claims and argues the opposite: Constitutional pluralism is not a valid normative or political theory for the European Union. The argument is based on detailed case studies of four legal mechanisms that have been enacted as a reaction to the European Union’s sovereign debt crisis. Furthermore, the study discusses the methodological and epistemological challenges that European constitutional pluralism gives rise to.