In the 2012 presidential elections, American voters cast 126,849,296 votes and only about 50% of the U.S. population who could vote, did vote. Brazil has 142,000,000 registered voters and they have mandatory voting, albeit it all-electronic voting. However, they use Diebold voting machines that are banned in the U.S., Holland, Germany, and--no-kidding--Paraguay. If we mandated voting, our large population and vast geography would require an all-electronic voting system. The choice of all-electronic voting system manufacturers would itself become a political issue, along with all the other worries about security, hacking, etc. Not sure how we square that circle.