Let’s assume you’re a US citizen, and let’s assume you care about the country. And let’s assume you plan to vote for the president this year — either because you think your vote might affect the outcome, or because you think it’s your civic duty as a citizen of a democracy.
Who should you vote for?
Well, the original field of 10,000 candidates has been winnowed down to just two that have any realistic hope of winning: Barack Obama and John McCain. Since one of the two will win, it should be simple enough to figure out which one would be better.
But in fact it’s not that simple.