The 14th amendment grants citizenship to all of the people born in the U.S. and gives them equal protection under law
Ex-slaves still cant get equal protection under laws. They still can't testify in trials.
The 15th Amendment was added to the US constitution in 1870. It grants 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."