Popular name for US Acts designed to enforce federal law. Such an Act was passed in 1833 and was designed to counteract nullification: it empowered President Andrew Jackson to use the army and navy, if necessary, to enforce the laws of Congress. Four Enforcement Acts of Congress (1870–75) were intended to compel recognition by the South of the Civil Rights Act of 1866, of the Fourteenth Amendment and later, the Fifteenth Amendment: Congressional elections were placed under national control, and the acts of armed organizations such as the Ku Klux Klan were declared tantamount to rebellion.