The 26th Amendment to the U.S. Constitution lowered the voting age of Americans from 21 to 18. The amendment was ratified in 1971 after years of debate about young men being sent off to war but being unable to vote.
During World War II, the draft age had been lowered to 18, but the voting age had stayed the same. Some states, such as Georgia, lowered the voting age for local and state elections, but until 1971, the federal voting age stayed at 21.
In 1970, the Supreme Court decided that Congress had the power to change the voting age but only at the federal level. To bypass that ruling, Congress decided to ratify a new amendment, which was subsequently signed by President Richard Nixon.