Congress expands suffrage in nation’s capital

On January 8, 1867, African-American men were granted the right to vote in Washington, D.C. despite President Andrew Johnson's veto. From the article:

"Congress expands suffrage in nation’s capital
Congress overrides President Andrew Johnson’s veto of a bill granting all adult male citizens of the District of Columbia the right to vote, and the bill becomes law. It was the first law in American history that granted African-American men the right to vote. According to terms of the legislation, every male citizen of the city 21 years of age or older has the right to vote, except welfare or charity recipients, those under guardianship, men convicted of major crimes, or men who voluntarily sheltered Confederate troops or spies during the Civil War. The bill, vetoed by President Johnson on January 5, was overridden by a vote of 29 to 10 in the Senate and by a vote of 112 to 38 in the House of Representatives.

In the aftermath of the Civil War, the Republican-dominated Congress sought to enfranchise African-American men, who thus would be empowered to protect themselves against exploitation and strengthen the Republican control over the South. In 1870, in a major victory in this crusade, the 15th Amendment to the U.S. Constitution was ratified, prohibiting all states from discriminating against potential male voters because of race or previous condition of servitude."