By lowering the voting age to 18, Japan hopes that young people will take a greater interest in politics. But if the United States is any guide, it's unlikely that the newly enfranchised youths will exercise their right as assumed.

In 1971, the U.S. lowered the voting age from 21 to 18 in large part because of the Vietnam War. The argument was that those able to fight for their country should be able to vote. As a result, the 26th Amendment to the U.S. Constitution was adopted.

But after the initial enthusiasm wore off, many newly eligible voters failed to cast their ballots. In fact, although voter turnout varies from election to election from year to year, younger voters consistently trail older voters by significant margins.