At the outset of the Civil War, five states, all in New England, allowed African Americans to vote on the same basis as whites. When the war ended in 1865, four million African Americans, now free citizens, many of whom had fought in the war, also wanted a share in the political process.
Historian Alexander Keyssar of Harvard University notes that federal government sought to give political rights to African Americans through the Fourteenth Amendment, which confirmed former slaves were American citizens deserving equal protection from state laws. But a clause in the amendment said that any state that denied the right to vote to a portion of its male black citizens would have its representation in Congress proportionately reduced. Says Keyssar: “Although this section of the amendment amounted to a clear constitutional frown at racial discrimination, and Congress hoped that it would protect black voting rights in the South, the amendment, as critics pointed out, tacitly recognized the right of individual states to erect racial barriers.”
1870 saw the enactment of the Fifteenth Amendment, which said that the rights of citizens to vote should not be abridged by the United States or by any State on account of race, color, or previous condition of servitude. But Congress failed to act to enforce voting rights, leaving power in the hands of the states.
In the South, black freedmen were enthusiastically embracing democracy, voting in large numbers and taking their place in the new state governments being created as part of Reconstruction. But by 1890, southern states, ignoring the Fifteenth Amendment, had begun disfranchising black voters. Mississippi led the way, with a constitutional convention that included complex residency requirements, a poll tax, and a literacy test. Other states followed. Felony disfranchisement was part of this exclusion process, with many Southern states identifying minor offences like vagrancy that could be used to disfranchise African Americans. And the laws were effective. Keyssar notes that in Mississippi after 1890, less than 9,000 of 147,000 voting-age blacks were registered to vote, while in Louisiana, where more than 130,000 African Americans had been registered to vote in 1896, the figure plummeted to 1,342 by 1904. Other states began disfranchising felons, too. From 35 per cent of states with broad felony disfranchisement laws in 1850, 96 per cent had such a law by 2002.
In fact, African Americans in the South remained largely disfranchised until the civil rights movement righted the situation. Congressman John Lewis sees the need to end felony disfranchisement as the next step in the struggle for civil rights. And in a paper on racial threat and felon disfranchisement in the United States from 1850-2002, authors Behrens, Uggen and Manza conclude that racial disparities in punishment still drive voting restrictions on felons and ex-felons today.
Reference: Alexander Keyssar, The Right To Vote: The Contested History of Democracy in the United States (Basic Books, 2000).
Other useful links: http://www.sentencingproject.org/pdfs/mauer-crj.pdf