The Northeast -- More socially conservative Democrats, but Casey and Biden (who was born in Scranton) should provide hometown pride for Democrats to seize this region for Obama.

The Center -- A few urban pockets (including more progressive Dauphin County, home to the state capital), but these counties are bedrock GOP country. McCain may not be Bush and is not beloved, but for these counties, Obama is a liberal from way beyond their world. Agriculture, guns and God all play huge here, so McCain sweeps.

The Lehigh Valley -- This will be a battleground. Obama needs to win here (and can) but needs to campaign hard; McCain has a small chance to eke out a win but more than likely will lose Northampton County, where an emerging Hispanic populace could be a decisive factor.

Philadelphia’s “collars” -- In Philly, black voters will provide a sweep for Obama. Philly’s four suburban collar counties also should go for Obama -- but McCain can appeal to a large Jewish populace on Israel, on his strong military background and on his maverick views.  Bucks and Delaware counties have large Catholic populations that Biden (who shares their Philadelphia media market) can influence. Run right, the McCain campaign can win Chester and Bucks counties but probably will lose Montgomery.

“Pennsylvania is a must-win for the Democrats,” Purdue professor Bert Rockman insists. “If the Republicans win it, then it is likely that Ohio will also fall their way, too, and very likely Indiana as well.

“So, as Pennsylvania goes …” Rockman says, his voice trailing off into an unspoken conclusion: so goes the nation -- and the presidency.