So one of the more interesting explanations of the McCain camp's move to Pennsylvania is that the Obama camp faked them out:

The Obama campaign is doing a major head fake in PA. They "accidentally" leaked an "internal" poll showing Obama up by only 2 percent in PA. I guarantee you that no such poll exists and that this was done both to motivate volunteers in the state (and maybe elsewhere) and prevent them from getting too complacent and also to sucker the McCain campaign into spending more time there. Ed Rendell has asked Obama to come back and campaign in the state-another major ruse. They know that McCain makes most of the decisions for his campaign and that they can goad him into spending more time in PA by pretending that it is close there. Let's see if Obama actually returns to PA before November 4th, but I sincerely doubt it. They are brilliant.

This was forwarded by a New Republic reader. The idea that Obama leaked fake polls is pretty ingenious. I'm not sure it's entirely accurate. There is the simple electoral math: McCain cannot win this election without turning a blue state red; he probably can't win this election anyway. If the reader is right, however, that would be a very exciting thing.