This book discusses the impact of the difficult situation the European Union is currently going through on some structural elements of its legal order, looking for symptoms of decay, exploring examples of resistance, and assessing its overall state of health. The original choices made by the drafters of the Treaties and by the Court of Justice are put in their proper historical perspective, understanding Union law as a tool of civilization, and explaining its current problems, at least in part, as a consequence of the waning of the initial impetus behind integration. The concrete themes to be explored are the following: primacy, the national resistance to it and constitutional pluralism; the preliminary rulings procedure; Union citizenship, equality, and human dignity; the scope of the Charter and the standard of protection of fundamental rights; and the rigidity and fragmentation of the Union system in connection with the recent occasional use of international law as an alternative to Union law. The book looks at the development of the law throughout the decades, inevitably losing much detail, but hopefully also uncovering structural connections and continuities.