Let’s say it’s Election Day 2008. You really, really, really want to vote for the Democratic nominee for president, Sen. Hillary Rodham Clinton (N.Y.), but you’re not registered to vote. You also don’t have a driver’s license or any sort of official photo identification that would tell the people down at the polling place who you are. You don’t even have anything to show that you’re an American citizen. But it’s Election Day, and you still want to vote for Clinton. What do you do? Well, you go right down to that polling place, tell them you want to register,...