Reconstruction was the period after the Civil War where the federal government sought to reunite the country and guarantee rights to freed slaves. Key events included the ratification of the 13th, 14th, and 15th Amendments abolishing slavery and guaranteeing citizenship and voting rights. However, southern states passed Black Codes and Jim Crow laws to restrict black rights. The Ku Klux Klan used violence against blacks. Reconstruction ended in 1877 when federal troops withdrew, leaving blacks without protection against discrimination and disenfranchisement.