Not sure I follow the logic. Hoeffel received only 42% of the vote in PA. Given the fact that Bush lost narrowly, and PA has already sent Rick Santorum to DC, I think the most likely scenario is a Toomey win.
Could it be that a lot of moderate dems crossed party lines? Could it be because Hoeffle didn't have a lot of money to campaign with? Could it be that the crat party figured that Spector was unbeatable and didn't mount a real push?
As far as Santorum goes I don't think he'll be able to be re-elected. There is a big block of left wing dems out east, a large group of embittered conservatives in the center of the state that are being urged to hold back their support of Rick because he supported Spector.