Let me guess...if he were to overturn Brown V Board or find the CIvil RIghts Act unconstitutional you would still call him mainstream...huh?
You really need to educate yourself regarding civil rights laws. Brown v Board of Education (1954) simply overturned the earlier Plessy v Ferguson (1896) case which confirmed that separate but equal was constitutional and enforceable. It was based on a passenger train going through the state of Louisana. A passenger, who was 1/4 black, was riding in the passenger car for whites. He was forced out of the passenger car for whites and into the car for blacks. He sued and lost. The Court ruling that both passenger cars were on the same train, leaving at the same time and going to the same destination.
Since the passage of several Civil Rights Acts, the case is moot.