Ulrich Hufeld reconstructs the constitutional breach as an independent category of constitutional change. Drawing on the history of concepts, the author emphasizes its material aspect: the exception at the constitutional level. The first chapter recalls the Weimar debate, the politically existential interpretation of the constitutional breach by Carl Schmitt, and the equality question raised by Gerhard Leibholz. After the Basic Law came into effect, the constitutional salvaging of the European Defense Community brought previously thought-overcome issues back to the forefront, as highlighted by Article 79 of the Basic Law. Against this historical backdrop, the author analyzes new forms of constitutional breach. The Europe Article 23 now directs integration legislation into the regime of Article 79 of the Basic Law.