Exchange Exemplar: When Congress Closed The Immigration Gate
The late 1910s and early 1920s featured a notable rise in bigotry in the United States. Witness the events: the return of the Ku Klux Klan, the race massacres in Tulsa and other towns, the backlash against foreign immigration.
They succeeded to some degree in raising white power and lowering the power of groups perceived as non-white. Those included people from Europe, who had the door shut on them in act of Congress in 1924.
Daniel Okrent tells the story in the book The Guarded Gate: Bigotry, Eugenics, and the Law That Kept Two Generations of Jews, Italians, and Other European Immigrants Out of America. This interview from 2019 details the long lead-up to the law, and how the case against some groups of people a "inferior" was built.