The Reconstruction Acts of 1867 to 1868 created five districts in the seceded states, headed by a military official who had the power to appoint and remove state officials; allowed all freedmen the right to vote; required states to draft documents providing for black male suffrage and permitted Southern states to rejoin the Union with the ratification of the 14th Amendment. President Andrew Johnson vetoed these measures but was overridden.
After the Civil War, Congress sought to reintegrate the 11 seceded states back into the Union, starting during the Lincoln administration. After his assassination, Johnson took over and continued Lincoln's more moderate plans, angering Congress and the Radical Republicans, who resented the relatively lenient policies. Most Southern states rejected the 14th Amendment, which extended citizenship to former slaves, but they were unable to prevent its ratification.
In response, the Southern states passed the black codes, which severely restricted the former slaves' freedoms and reduced them to borderline slave labor once again. This in conjunction with the race riots led the Radical Republicans to assume control of Congress and pass the Reconstruction Acts, which installed in the Southern states governments made of African-American men, carpetbaggers and scalawags. Southerners resented these governments and remained hostile to them, viewing them as artificial constructions.