Which amendment lowered the voting age for U.S. citizens to 18?

The Twenty-sixth Amendment lowered the voting age for U.S. citizens to 18.

The amendment prohibits federal and state governments from denying or abridging the voting rights of citizens aged 18 or older because of age. It was ratified on July 1, 1971, becoming part of the Constitution during a period of intense debate about youth and civic participation.

Support for the change grew during the Vietnam War era. The slogan “old enough to fight, old enough to vote” captured an argument that young adults who could be drafted for military service should also have a voice in elections.

Before the amendment, the standard voting age in most states was 21. Congress had passed the Voting Rights Act amendment in March 1971, and the states completed ratification in just over three months, one of the fastest constitutional amendment processes in U.S. history.