Constitutional ambiguity has been an important enabler of European integration. Achim Hurrelmann argues that although this can cause problems, it often remains the best option for holding the European Union together and has shaped how the EU has responded to its recent crises.

This book reinterprets European integration as being based on the concept of "constitutional abeyances" - originally developed by Michael Foley and not previously applied to the EU - which are unresolved issues that subsequent political elites avoid politicizing to prevent conflict. Hurrelmann shows that it is a concept that can help us better understand the EU: what it is, how it works, why it sometimes does not work, and how it responds when crises hit. He shows that, although these strategies may be criticized, they ultimately have contributed to the EU's resilience in face of the crises over the euro, migration and rule of law.