My sense of things had been that, demographically speaking, Pennsylvania was like Ohio but I thought I might look up the actual census data to see what we can see. Basically, Pennsylvania is like Ohio. The differences -- more old people, fewer black people, more Hispanics -- mostly cut in Clinton's favor, with only the larger number of college graduates helping Obama. The bad news for Obama, basically, is that he needs to fight a big, protracted battle in a state that's very demographically unfavorable to him.
The good news for Obama is that given how Clinton-friendly the state and, and the fact that Clinton can't overtake him in the delegate lead anyway, if he does manage to beat her here she'll have no excuses left to stay in the race.