The National Voting Rights Act of 1965 was a landmark piece of civil rights legislation in the US which outlawed literacy testing because the practice was being unfairly used to deny African-Americans their right to vote. Not only did this act end literacy testing, it established an extraordinary regime of federal oversight of the election practices of those states with egregious violations of African-Americans' voting rights.
At the end of the US Civil War, three amendments to the US Constitution &emdash; the Thirteenth, Fourteenth, and Fifteenth &emdash; were ratified. Among other things, these amendments ended the practice of slavery, granted ex-slaves US citizenship, and forbade the states from denying citizens the right to vote on account of their race or former condition of slavery. During the period of Reconstruction, which lasted until 1877, those states were forced to hold elections in which freed slaves voted. After 1877, when Federal troops left the last of the Southern states, they began exploring different ways to disenfranchise African-Americans &emdash; that is, deny them their right to vote &emdash; without either violating the Constitution or abridging the right of white people to vote. Other than intimidation and violence, two of the more popular methods of denying voting rights were poll taxes and literacy tests.
Poll taxes were simply that — a tax imposed on anyone who voted. These taxes weighed more heavily on the poor, and most freed slaves and their descendants in the south were very poor. They were found to have a discriminatory effect and were outlawed in 1964 with the ratification of the 24th Amendment to the Constitution.
Literacy tests were far more pernicious. First appearing in the south in the 1890s, the laws establishing them often grandfathered, or exempted from the tests, anyone whose grandfather had voted in any election prior to the Civil War &emdash; in other words, a time when only white males could vote. Anyone who wasn't grandfathered had to pass a literacy test, which usually consisted of the voter being handed a paragraph to read and explain to the testing official. It was found that whites &emdash; even those who couldn't even read &emdash; were provided with simple nursery rhymes and similarly easy material, and always passed. African-Americans, on the other hand, were given complex paragraphs, often sections of the Constitution, and no matter how well they read and explained the text, they were declared illiterate. Although the Civil Rights Act of 1964 addressed the literacy tests, it didn't end them entirely, and it wasn't until the passage, one year later, of the voting rights act of 1965 that this patently discriminatory practice was finally outlawed.
In addition to outlawing literacy tests for voters, The Voting Rights Act of 1965 imposed a severe regime of federal supervision of those states, all in the south, that had the most egregious patterns of disenfranchisement. In a significant break with established tradition, for example, those states were required to seek approval from the Justice Department before making any changes at all to their election procedures. Other states typically could make whatever changes they cared to, and had to account for them to the Justice Department only if a valid complaint was made.
The Voting Rights Act of 1965 was a landmark piece of civil rights legislation because it not only ended a specific discriminatory practice, it put the states on notice that the rights of citizens to vote was under the special protection of the federal government. While states may still determine who may and may not vote in elections &emdash; there's no Constitutional right to vote &emdash; whatever standards and qualifications they impose must be applied fairly across the board, and may not be influenced by the voter's gender or race, or age if 18 or older. In addition, any qualifications imposed may not disproportionately affect members of any protected group.