The 15th Amendment to the Constitution granted African American men the right to vote by declaring that the "right of citizens of the United States to vote shall not be denied or abridged by the United States or by any state on account of race, color, or previous condition of servitude."Although the Amendment was passed, (ratified on February 3, 1870) it was not recognized for almost a century!
Groups were formed to keep the blacks the ability the vote (Voting Rights and Citizenship).
To keep the African Americans frustrated and away from voting they would turn to the means of:
The poll taxes kept poor blacks (along with poor whites) from being able to vote because they did not have the money to pay for it.
Lynching was the most common of racial violence that discouraged the African Americans from trying to vote.
With most blacks having no to little education, they could not pass the literacy tests given in order to vote. An example of a test would be to name all of the Vice Presidents and Supreme Court Justices throughout America's history.
"So long as Negroes were slaves, so long as they posed no threat to the political and economic supremacy of whites, men were content to live with them on terms of relative intimacy. But when the slave became a citizen, when he got a ballot in his hot hand and a wrench and pencil and paper Ă‘ well, something had to be done with him" ( Jim Crow laws denied blacks dignity, vote ).