Security has been at the heart of European integration, in one way or another, since the entry into force of the Maastricht Treaty. A series of terrorist attacks in the 2000s, including 9/11, 7/7 and the Madrid bombings, has been followed by a plethora of responses by the EU legislator, with EU intervention being justified as emergency law and pushing boundaries in criminal law and the constitutional systems of the Union and its Member States. This pattern of EU response has been replicated after successive terrorist incidents, resulting in a patchwork of measures adopted swiftly, without detailed justification or impact assessment and resembling at times kneejerk reactions or quick fixes to complex issues, while presenting significant challenges to fundamental rights and the rule of law in Europe. In recent years, the development of a European security strategy and the publication of regular reports on the Security Union might be said to represent a more strategic response. The Security Union reports, however, betray a tendency to pursue relentlessly and uncritically a security agenda without due consideration for the protection of fundamental rights and the rule of law.