Parsing the early vote: Who’s winning?

With more than 27 million Americans having already voted, the Obama and Romney campaigns have found a new topic for disagreement: what do the numbers say about who is winning?

That’s around 20% of the total.

Has the election already been decided? If so, why should I show up to vote?

This must be what it felt like to live in Hawaii, when the national media already declared a winner while you’re still on the way to the polls.