1966 when LBJ signed the Civil Rights Act. Prior to that minorities were more likely to be Republican then anything else.
But LBJ got all the credit for being "The Great Reformer" even though it was his own party that opposed the bill and the Republicans in the House and Senate who sent it to him.
For some reason Americans have an interesting blind spot as to who creates the laws. A President is given credit or blame for a law that he may not have much choice about signing.
Republicans were also the ones who fought and passed legislation that gave women the right to vote and passed Indian Citizenship Act that made American Indians legal citizens of the USA.
Somehow all of these things have gotten lost in the fog of mis-taught history.
Interesting and thank you very much for the history lesson. :)