In some places, the Ku Klux Klan (KKK) was a social fraternity whose members enjoyed sophomoric hijinks and homemade liquor. In other areas, the KKK was a paramilitary group intent on keeping former slaves away from white women and Republicans away from ballot boxes. South Carolina saw the worst Klan violence and, in 1871, President Grant sent federal troops under the command of Major Lewis Merrill to restore law and order. Merrill did not eradicate...