This article discusses the Federal Constitutional Court’s contribution to European “integration through law” over the past decades. The Basic Law’s openness to integration and to European Law is examined, as well as the co-operation between the Federal Constitutional Court and the European Court of Justice in the execution of European Union law and the protection of fundamental rights. The author provides a number of examples to show how the instruments of identity review and ultra vires review developed by the Federal Constitutional Court secure the agenda of European integration as agreed upon in the European Treaties. He also shows how national governmental bodies are bound by the concept of responsibility with respect to the European integration process and how the Court ensures the necessary democratic legitimisation for the acts of European institutions by requiring the involvement of the German parliament in political decision-making processes related to the European Union. Finally, the author explores the idea of the legal community and the criticisms that have been levied against this concept. He concludes by positing that the European Union can only preserve itself by remaining a legal community, and that the rule of law in EU law is indispensable, particularly in times of crisis.