The systematic killing of institutionalized patients with disabilities in Germany, known as the Euthanasia Program (T4), occurred approximately two years before the Holocaust and was one of several eugenic measures intended to restore the racial “integrity” of the German nation.
The program sought to eliminate those deemed “life unworthy of life” by eugenicists and their supporters, who believed that individuals with severe psychiatric, neurological, or physical disabilities posed a genetic and financial burden on German society and the state.

“Reich Leader Bouhler and Dr. Brandt are entrusted with the responsibility of extending the authority of physicians, to be designated by name, so that patients who, after a most critical diagnosis, on the basis of human judgment [menschlichem Ermessen], are considered incurable, can be granted mercy death [Gnadentod]. — A. Hitler”