Something odd is going on there. Don't know what it is. Possibly the players there are just watching the public polls. From reading some of the posters comments there, they don't seem to be very sophisticated people in that marketplace. I guess if you trusted that market to actually pay if you win and you could get off any size, it might be a good short. It's not a game I would play though.
And, I agree with others. It could be manipulated by a large player to make it look good for Obama. That would mean it would be a good short for anyone wanting to play for the end game.