German legal doctrine began to provide its arguments for the suppression of “lives unworthy of being lived” in the 1920s. But it is with the advent of Nazism and the outbreak of World War II that these formulations move from the level of hypotheses to that of concrete realizations. A vast and widespread program of euthanasia fell on Germany, wiping out adults and children guilty of not meeting the parameters of physical and mental perfection established by the regime. In the post-war period, numerous trials were held, with the aim of shedding light on this extermination and consigning the creators and executors to the due expiation of the legal faults of which they were guilty. A goal that, for a set of national and international political convenience, remained largely unachieved and eventually buried by a mountain of legal sophistry.