After the Thirteenth Amendment abolished slavery in America, racial discrimination became regulated by the so-called Jim Crow laws, which mandated strict segregation of the races. Though such laws were instituted shortly after fighting ended in many cases, they only became formalized after the end of Republican-enforced Reconstruction in the 1870s and 80s during a period known as the nadir of American race relations. This legalized segregation lasted up to the 1960s, primarily through the deep and extensive power of Southern Democrats.