Civil War and the amendments after.
Hey all you slaves, your now free. President Lincoln, and the North freed you, so go make a life for yourself and your future generations.
Now guys, thanks to the 14 amendment every body has equal protection by the law. Also, if you were born on U.S soil you are a U.S citezen.
Now, all men have the right to vote, even if you black! Sorry women, your time will come.