The 15th Amendment of the U.S. Constitution states that neither the nation nor any individual state can deny or change the voting rights of an American citizen, regardless of his race, color or past experiences as a slave. It was designed to give African-American men the right to vote.
The amendment also gave Congress the power to enforce the new law. It was formally adopted on March 30, 1870, five years after the Civil War had ended. The success of this amendment, however, was not immediate. Some states, particularly in the South, devised indirect ways to bar black men from voting. This resulted in the 1965 Voting Rights Act, which was passed to prohibit poll taxes and other "rules" that effectively disenfranchised a portion of eligible citizens.