Combining rich theoretical analysis with real-world examples, this erudite book navigates EU law in the context of hybrid threats, examining how security issues affect themes of constitutional law at the heart of a democratic system. Presenting doctrinal and historical insights, the book not only considers the different types of hybrid threats, but also how they are increasingly showing that traditional understandings of security risk are becoming obsolete.Bringing together leading experts in the fields of security, anthropology, and EU law, chapters map out the EU and NATO’s responses to five hybrid threats: disinformation, instrumentalisation of migration, cyberthreats, abuses of energy resources, and lawfare. The book focuses on both security and legal issues and answers two interrelated questions: what is the nature of a hybrid threat? And what legal tools are available to the EU to protect its citizens from those threats? The answers to these questions reveal how hybrid threats put increased tension on the capacity of a democratic system to resist rival models.Interdisciplinary in scope, this will be a fundamental resource for researchers, academics and students of European law, terrorism and security law, politics, and international relations. Legal practitioners with a keen interest in EU constitutional law, common foreign and security policy, and internal market regulation will similarly find this to be an indispensable read.