force bill, popular name for several laws in U.S. history, notably the act of Mar. 2, 1833, and the Reconstruction acts of May 31, 1870; Feb. 28, 1871; and Apr. 20, 1871. The first force bill, passed in response to South Carolina's ordinance of nullification, empowered President Jackson to use the army and navy, if necessary, to enforce the laws of Congress, specifically the tariff measures to which South Carolina had objected so violently. In the second set of force bills, or enforcement acts, as they were also called, the radical Republicans controlling Congress strengthened their Reconstruction program for the South by imposing severe penalties on those Southerners who tried to obstruct it. The act of May 31, 1870, designed to enforce the Fifteenth Amendment, provided heavy penalties of fine and imprisonment for anyone preventing qualified citizens (in this case African Americans) from voting. Such cases were to come under the jurisdiction of the federal courts. Congressional elections were placed exclusively under federal control, and the President was authorized to use the armed forces. In a similar vein but even more drastic was the act of Feb. 28, 1871. The act of Apr. 20, 1871, inspired by the activities of the Ku Klux Klan, declared the acts of armed combinations tantamount to rebellion and empowered the President to suspend the privilege of habeas corpus in lawless areas. President Grant did this in certain counties of South Carolina. Hundreds were indicted, fined, and imprisoned, and the act was partially responsible for the subsequent decline of the Klan.