Much of the impetus for Reconstruction involved the question of civil rights for the freed slaves in the southern states. In response to efforts by southern states to deny civil rights to the freed slaves, Congress enacted a civil rights act in 1866 (and again in 1875). This led to conflict with President Andrew Johnson, who vetoed the Civil Rights Act of 1866; however, his veto was overridden.
After solid Republican gains in the midterm elections, the first Reconstruction Act was passed on March 2, 1867; the last on March 11, 1868. The first Reconstruction Act divided ten Confederate states (all except Tennessee, which had been readmitted on July 24, 1866) into 5 military districts. Governments that had been established under Abraham Lincoln's plan were abolished; the first Reconstruction Act stated that "no legal State governments or adequate protection for life or property now exist in the rebel States".
During the period of Reconstruction there was considerable upheavel in Southern society. Northerners, known as carpetbaggers, moved south to participate in southern governments. Republicans assumed control of all state governments, and began to pass numerous civil rights laws, legalizing interacial marriage, ensuring black schools, and variety of other abitious proposals. In many cases former slaves were given very prominant ranks in the government, usually as state senators or state legislators. There were also numerous black judges, mayors, sheriffs, and deputy governors installed. Louisiana even had a black governor for a brief period. Most political "firsts" for African Americans occured during this period.
The rapid rise of the black population caused considerable racial tension. White southerners who joined the Republican party were derisively called scalawags. Anti civil-rights terrorists denounced the "black mob rule" and formed violent organizations like the Ku Klux Klan.
Three constitutional amendments were passed in the wake of the Civil War: the thirteenth, which abolished slavery; the fourteenth, which granted civil rights to African Americans; and the fifteenth, which granted civil rights to freed citizens. The fourteenth amendment was opposed by the southern states, and as a precondition of readmission to the Union, they were required to accept it (or the fifteenth after passage of the fourteenth). All Southern states were readmitted by 1870 (Georgia was the last on July 15), and all but 500 Confederate sympathizers were pardoned when President Ulysses S. Grant signed the Amnesty Act on May 22, 1872. However, Reconstruction continued until 1877, when the contentious Presidential election was decided in favor of Rutherford B. Hayes, supported by Northern states, over his opponent, Samuel J. Tilden. Some historians have argued that the election was handed to the Hayes in exchange for an end to Reconstruction; this theory characterizes the settlement of that election as the "Compromise of 1877". Not all historians agree with this theory; in any case, regardless of the circumstances, Reconstruction came to an end at this time.
The end of Reconstruction essentially signalled the end of civil rights for African Americans; as the years passed after the end of the war, the North lost interest in continuing to pursue the matter and instead turned its attention towards other concerns.
The South was allowed to establish a segregated society in return for accepting its integration into the Union, and the initial flurry of civil rights measures were eroded over time. In the aftermath of Reconstruction, much of the civil rights legislation was later overturned by the United States Supreme Court. Most notably, the court suggested in the "Slaughterhouse Case" 83 US 36 (1873), then held in the Civil Rights Cases 109 US 3 (1883), that the Fourteenth Amendment only gave Congress the power to outlaw public, rather than private discrimination. Plessy v. Ferguson 163 US 537 (1896) went even further, providing that state-mandated segregation was legal as long as the statute or ordinance provided for "separate but equal" facilities.
The Supreme Court maintained the fiction of "separate but equal" for many years until finally abandoning it and reversing "Plessy" in Brown v. Board of Education of Topeka 347 US 483 (1954). It was not until 1964 that the federal government made a concerted attack on the system of private racial discrimination that had become entrenched in the shadow of state Jim Crow laws when it passed the Civil Rights Act of 1964, which outlawed discrimination in "public accommodations," i.e., restaurants, hotels and businesses open to the public, as well as in private schools and workplaces.