Which U.S. constitutional amendment lowered the voting age to 18 in 1971?

The Twenty-sixth Amendment lowered the voting age in the United States to 18 in 1971.

Congress proposed the amendment on March 23, 1971, and Ohio became the 38th state to ratify it on June 30, 1971. The amendment was certified on July 5, 1971, making it the fastest constitutional amendment to move from proposal to ratification at that time.

The campaign gained strength during the Vietnam War, when many people argued that citizens who were old enough to be drafted and serve in the military should also be able to vote. The slogan “Old enough to fight, old enough to vote” became closely associated with the movement, although the amendment applies to all federal, state, and local elections.

Before the amendment, most states set the voting age at 21, but a few had already lowered it. The Supreme Court’s 1970 decision in Oregon v. Mitchell created uncertainty about congressional power over voting ages, helping prompt the amendment’s rapid adoption. The Twenty-sixth Amendment remains the youngest voting-age standard in the Constitution.