McCain has spent a good portion of this final weekend campaigning in Pennsylvania, even though he still trails by 7-points in the latest RCP Avg. However, he trailed by about 14-points in early October, so halving that is admirable.

More to the point, if McCain can pull out a victory in Pennsylvania, he's made Obama's path to victory that much harder. That McCain is spending so much  time there probably means that his campaign has figured how election night is likely to go -- with certain states like Florida, North Carolina and Indiana turning his way.  That puts the focus on just a few battlegrounds and Obama's easiest path to 270 goes through PA.  Knock Obama off there, McCain figures, and he's got to win Ohio (+4.2 for Obama), probably Virginia (+5 for Obama) and a state out West like Nevada (+5.8 for Obama) or Colorado (+5.5 for Obama). All of which, looking at the averages, is certainly doable, just harder if Obama loses Pennsylvania.

That, anyway, is how it looks playing around with the RCP Electoral Map.

UPDATE: In his 50-State Breakdown, this is what Chuck Todd says about PA:

Pennsylvania: Ah, the Keystone state. Is it in play or not? The McCain folks have no choice but to believe that it is. They are hoping that party I.D. snaps back and that some sort of race component kicks in to salvage McCain. I don't know. If George W. Bush couldn't carry the state, why should we believe McCain can? Ironically, Republicans have a shot at winning two House seats thanks to incumbent Democratic gaffes; Both Jack Murtha and Paul Kanjorski are on the brink. Could Pennsylvania be the only state in the union where Republicans net more House seats than Democrats?