Southern governments implemented a series of devices that would stop African-American citizens from voting including:
1) Poll Taxes- This was a certain amount of money an individual had to pay in order to vote. Many African-Americans could not afford these taxes.
2) Grandfather Clauses- This was a law that essentially stated that you were only able to vote if your grandfather voted. When this was first implemented, many African-American citizens were slaves before or their family members were slaves.
3) Literacy tests- These near impossible tests were based on a person's ability to read and write. This was effective when first implemented because many African-Americans did not have formal schooling due to their status as slaves before the end of the Civil War.
The NAACP was the National Association for the Advancement of Colored People- the name already shows you that they were interested in racial equality! They filed the case in order to repeal and forbid the practice of having racial segregation at schools - and they won!