US Roots of Nazi Racism
It wasn't just laws. The first half of the Twentieth Century was the high water mark of so-called scientific racism, and the US was its epicenter. Two books in particular got a special place on Hitler's bookshelf: Madison Grant's The Passing of the Great Race, and Henry H. Goddard's The Kallikaks.
The first attempted to prove that all the accomplishments of civilization were due to so-called Nordics and that race mixing always resulted in dominance of the supposed inferior race: Blacks, Jews, Italians and so on. Goddard's book traced the supposed history of a family of imbeciles, degenerates and criminals.
These were by no means fringe publications. Grant's supposedly got a forward from Teddy Roosevelt and Goddard was feted at scientific conferences. Oliver Wendell Holmes propounded from the Supreme Court that "three generations of imbeciles are enough."
Few contested these popular myths, but those who did included some of the pioneers of genetics who already knew that this stuff was crap, and notably, Franz Boaz and his students.
Boaz was a Jew, a German University graduate with a face liberally decorated with dueling scars, and one of the principal founders of American anthropology. Boaz had spent a significant portion of his early career measuring physical and other characteristics of immigrants and other of all races and his data persuaded him that conventional racist dogma was nonsense.
Somewhat amazingly, long before the discovery of the nature of the gene and the human genetic code he already propounded the idea that race was a social construct rather than an immutable human characteristic. Modern genetic studies have shown just how prescient this insight was. Human diversity within any so-called race is much greater than diversity between such races.
After World War II, general horror at Hitler's methods brought Eugenics and related ideas into disrepute. Goddard and Grant had been exposed as deluded or charlatans, and the science of genomics validated Boaz.
(Notes for a review of Gods of the Upper Air: How a Circle of Renegade Anthropologists Reinvented Race, Sex, and Gender in the Twentieth Century by Charles King )