Final answer:
The 26th Amendment to the United States Constitution, which lowered the voting age from 21 to 18, was ratified by three-fourths of the states in a relatively short period of time.
Step-by-step explanation:
The 26th Amendment to the United States Constitution, which lowered the voting age from 21 to 18, was ratified by three-fourths of the states in a relatively short period of time. It took only a few months for three-fourths of the states to ratify the amendment after it was proposed by Congress in 1971. This was due to the widespread support for the amendment, as many people believed that young men who were fighting in the Vietnam War should have the right to vote.