Twenty-sixth Amendment to the United States Constitution
Lowering the minimum voting age was not a new idea.  In the United States, some people started trying to get the voting age lowered during World War II.  During the war, President Franklin D. Roosevelt lowered the military draft age to 18.  This meant that men as young as 18 could be forced to join the military.  To many people, it did not seem fair that the government thought these young men were old enough to fight a world war, but not old enough to vote in the country they were fighting for.  "Old enough to fight, old enough to vote" became a common slogan.