Amendments 15, 19, and 26 all deal with suffrage. Suffrage is

The right to vote in political elections. 15 Prohibits the denial of the right to vote based on race, color, or previous condition of servitude. 19 Prohibits the denial of the right to vote based on sex. 26 Prohibits the denial of the right of US citizens, eighteen years of age or older, to vote on account of age.