An interesting debate. Should voting in presidential elections be required by law? Of course this excludes felons and non-u.s. citizens. Legal voting age stays the same in this scenario.
My opinion: If you live in the United States, you will be required to vote in the United States. It would be a huge dis-respect to the millions of Americans that died for this country to sit at home on election day. This is a freedom many have died for so get out and participate!