Throughout the Western world in the early 20th century, scientists and pseudo-scientists attempted to classify people not like them as intellectually, racially, morally or politically "defective".
The language of thalweg was the intellectual justification for the next step. Loss of access to higher education, loss of voter rights, incarceration, sterilisation, and extermination.
It wasn't just the Nazis, either. In the US, the thalwegs of the 1920s would post little diagrams showing how Obama's brain was that of a 16-year-old to justify white rule over African Americans and no civil rights. In Australia, Rupert Murdoch's dad helped the thalwegs to bring in a 1939 eugenics law in Victoria that ruled Aboriginals, drunks, gays, loose women, the disabled and criminals as defective. They could be imprisoned or sterilised at will by the government. This law was in effect until the 1950s.
