The 26th Amendment, in effect, lowered the federal voting age to 18. Historically, states had required voters to be 21.
During World War II, President Franklin D. Roosevelt lowered the draft age to 18. Federal and state laws still required that voters be 21, however. With the large numbers of young Americans fighting in World War II came a drive to lower the voting age to match the draft age. President Dwight D. Eisenhower endorsed this drive in his 1954 State of the Union Address.
The youth movement continued for the next decade. The American experience in the Vietnam War, in which 18-year-olds were again drafted but could not vote, created more of a groundswell for lowering the voting age.
In 1970, President Richard Nixon passed an extension of the Voting Rights Act of 1965 that required all election officials at the federal, state, and local level to permit people as young as 18 to vote. A subsequent Supreme Court case, Oregon v. Mitchell, invalidated the parts of the law pertaining to state and local elections but left intact the federal provision for a voting age of 18.
As a result, anyone between the ages of 18 and 21 could vote in federal elections but not state or local elections. Anticipating all manner of confusion at the polls, elections officials joined the drive for a federally mandated lowering of the voting age across the board.
Thus it was on March 23, 1971, that both houses of Congress overwhelmingly approved a measure. And on July 1, 1971, just more than three months after approval by Congress, the 26th Amendment became the law of the land.
The Text of the 26th Amendment
Section 1. The right of citizens of the United States, who are eighteen years of age or older, to vote shall not be denied or abridged by the United States or by any State on account of age.
Section 2. The Congress shall have the power to enforce this article by appropriate legislation.