United States Senator John Scott of Pennsylvania formed a committee to take testimony about actions of the Ku Klux Klan in January 1871. In February of that year Congressman Benjamin Franklin Butler introduced an anti-Klan bill designed to enforce the Fourteenth Amendment. The original bill was defeated in the House, but Congressman Samuel Shallabarger of Ohio introduced a substitute bill that passed the House by a thin margin. The bill had no trouble passing the Senate and President Ulysses S Grant signed it into law April 20th 1871.
Under this Act, United States troops were brought in to enforce laws in the southern states where hundreds of members of the Ku Klux Klan were tried in Federal courts. As part of this Act Habeas Corpus was suspended in many of the counties of South Carolina. It wiped out the Klan and other white supremacy groups for many years in the former Confederate States.