15, 19 and 26 amendments

The 15th Amendment to the United States Constitution was ratified in 1870 and prohibits the denial of voting rights based on race, color, or previous condition of servitude. It effectively granted African American men the right to vote.

The 19th Amendment to the United States Constitution was ratified in 1920 and guarantees women the right to vote. It prohibits the denial of voting rights based on sex.

The 26th Amendment to the United States Constitution was ratified in 1971 and lowers the voting age from 21 to 18. This amendment was passed in response to the Vietnam War and the belief that if 18-year-olds were eligible to be drafted, they should also be allowed to vote.