That Kelsen was the principal defender of Morgenthau's "Habilitationschrift" is recently documented in the translation of Morgenthau's book titled "The Concept of the Political". In the introductory essay to the volume, Behr and Rosch indicate that the Geneva faculty under the examiners Walther Burckhardt and Paul Guggenheim were initially quite negative concerning Morgenthau's "Habilitationschrift". When Morgenthau had found a Paris publisher for the volume, he asked Kelsen to re-evaluate it. In the words of Behr and Rosch, "Kelsen was the right choice to assess Morgenthau's thesis because not only was he a senior scholar in "Staatslehre", but Morgenthau's thesis was also largely a critical examination of Kelsen's legal positivism. Thus, it was Kelsen to whom Morgenthau 'owed his "Habilitation" in Geneva,' as Kelsen's biographer Rudolf Aladár Métall confirms, "and" also eventually his subsequent academic career, because Kelsen produced the positive evaluation that convinced the board of examiners to award Morgenthau his "Habilitation"."