5 ideas
Weimar-era reform psychiatry, especially active work therapy, split patients into the curable and productive versus the chronic and incurable. When budgets tightened, that therapeutic distinction became a selection criterion: a patient's capacity for useful labour decided who stayed and who was deemed expendable. Progressive reform supplied the categories that killing later used.
The 1920 tract by the jurist Karl Binding and the psychiatrist Alfred Hoche recast incurable patients as 'ballast existences' whose care consumed resources owed to the healthy nation. Framing a person's worth as a net cost to the collective let killing be presented as a rational, even humane, reallocation rather than murder.
In 1920 the asylum director Ewald Meltzer surveyed parents of disabled children, expecting them to reject euthanasia, and published the results in 1925. Most said they would accept a painless death for their child, and many preferred that it happen without their being asked. The regime later exploited this wish to avoid responsibility, killing patients covertly and sending families false death notices.
In August 1941, the month of Bishop von Galen's public sermon, Hitler ordered a stop to centralised gassing, but the killing did not end. It continued inside individual asylums through starvation diets and drug overdoses, while the 14f13 selections of concentration camp inmates, begun in April 1941, were already under way before the halt.
T4 developed the core techniques of industrial murder: gas chambers disguised as showers, crematoria, deceptive processing of victims, and personnel practised in killing. Many T4 staff were then transferred to run the Operation Reinhard extermination camps. The murder of patients was a direct institutional and technical precursor to the extermination of the Jews.