. What did white Southerners do to try to stop blacks from voting?

Started the KKK and threatened violence to Blacks who voted for Republicans (they were the ones who abolished slavery, thanks to Abraham Lincoln). Also, they instigated Black Codes and certain taxes that most Black people could not afford.

Explanation:

Black Codes are laws spefically designed for African Americans

One method that was used was the poll tax. The poll tax required a person to pay a fee in order to vote. Since many African Americans were poor, they could not afford to pay the tax. As a result, they did not vote.

Another method that was used was the literacy test. The literacy test required a person to read and explain a part of the Constitution. Since many African Americans had limited education, many African Americans could not pass the test in order to vote. They used the KKK to terrorize blacks and passed black codes.

Explanation:

i also think he is correct. i believe they came to washington to protest their rights.