I've always thought that if Romney had a chance to win this election, he would. It should be remembered that not all roads to victory lead through Ohio. On the other hand, I've never seen the Democrats I know more motivated.
You might ask, why not forget the polls and just vote? Well, there is a certain category of fair-weather voter who likes to vote for the winner. There is another category of voter who likes to vote for the underdog, but by definition that is a smaller category. That means in a very close election "I'm going to win" is how you get those last swing voters.
In the perfect campaign, the candidate would collect both the underdog vote and the fair-weather vote, by targeted messaging of "I'm going to lose" and "I'm going to win." Could it be that the Obama campaign is just that smart?
Update: Now that we have the "official" results from Florida, it would appear that the predictions of an Obama victory weren't confident enough.