I think you'd better do a little research. Other than Jim Crow and white supremacy, the things you mentioned have been done for many years, true, but they have been practiced by different races, not just the "white man." And when the US South was in the post-slavery era it was the Democrats who fought to keep the white supreme, fought to keep segregation, held the political power that kept white-only voting for years. The first president in the 20th century to tackle segregation was Eisenhower. The senator who was chief in defeating his ideas was Lyndon Johnson.