The essay retraces the controversy between Hans Kelsen and Carl Schmitt on the 'Custody of the Constitution' in the light of the historical events of the end of the Weimar Republic. Methodologically, it starts from the idea that it is useful to study legal ideas as historically given in their political and social context. It will be shown how the theoretical positions of the two great jurists on the protection of the constitutional order, jurisdiction and emergency were reflected in the 1932 Prussia v. Reich trial. It is precisely this hard case that offers the opportunity to measure the impact of jurists, courts and institutional actors on a situation of ‘political’ emergency
