The rise of Euroscepticism and populist backlash pose a dramatic challenge to the EU and highlight the EU's growing legal powers over core areas of state sovereignty. Authored by leading academics and policymakers, this book provides a comprehensive and cutting-edge analysis of the fields of EU law at the heart of contemporary political debates—economic policy, human migration, internal security, and constitutional fundamentals at the national level. Following the specialist contributions, the conclusion draws out critical, cross-cutting lessons for improving legitimacy and advancing the rule of law, rights and democracy in sovereignty-sensitive areas of EU law. Accessible to students, this volume is an invaluable resource for researchers and scholars of EU law and politics.