[Between affirmation and negation: Karl Kleist and Viktor von Weizsäcker between 1933 and 1945].

In 1954 Karl Kleist (1879-1960) became an honorary member of the German Neurological Society (DGN), an honor that was granted 2 years earlier to his colleague Viktor von Weizsäcker (1886-1957). The attempt to classify and assess their careers between 1933 and 1945 led to diametrically opposed results in historical research. This article summarizes the main lines of argumentation and draws a preliminary conclusion. After 1933 Kleist is said to have felt more and more accountable for his non-Aryan colleagues and that he treated his Jewish patients as long as he could. Publications and third party testimonies confirmed that he circumvented at least occasionally the Law for the Prevention of Genetically Diseased Offspring (GzVeN). Furthermore, he is said to have saved patients from "euthanasia" actions by prudently formulated diagnoses. Simultaneously, he worked as an expert at the Appelate Hereditary Health Court in Frankfurt am Main, in 1940 he joined the National Socialist German Workers' Party (NSDAP) and in 1942 the NS Medical Association. Von Weizsäcker used his scope of action in a similarly contradictory way. Certainly, he kept away from central Nazi organizations and was considered "politically unreliable" by those colleagues who had a penchant for the system. But as professor of neurology he formally headed from 1941 onwards exactly that Neuropathological Research Institute in Breslau (Wroclaw) where one of his colleagues examined the brains of minors who had been killed in the course of "child euthanasia", in what was called "concomitant research". To a certain extent von Weizsäcker was also an advocate of the GzVeN. In his lectures and publications between 1933 and 1935 he chose the pertinent NS terminology and he was the first to speak of a "theory of extermination". In either case, even meticulous research could not answer the question where to exactly assign both biographies in a spectrum between criticism and affirmation of National Socialism.