This is, after all. politics.
It could very well be that Obama is doing better than the polls show and he doesn't want to lose momentum by being lazy. Could be the whole state of Pennsylvania is secretly going to vote for McCain when push comes to shove and they are alone in that voting cubicle.
Republicans skewer their way and Democrats another.
We won't know till the end of the day. And hopefully there will be no "Florida fiasco" to add confusion and uncertainty.

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218 Days till Christmas