This piece in Saturday's Washington Post says Obama won't necessarily be going all out in Pennsylvania:
With Pennsylvania looming, Obama has few good options. Some advisers say he should stick to a plan, hatched before Tuesday's defeats, to spend some time in the next weeks traveling to Europe, Israel and Asia to bolster his credentials for the general election. But if he cedes the state completely, he destroys his strategy of winning big in the small states and staying close in the big ones.
Axelrod and other Obama aides said they have learned their lesson from Tuesday. Rather than accept Pennsylvania as a tiebreaker, they will play down their chances there and keep the focus on states such as North Carolina and Indiana, where they think their chances are better.
I'd guess the first paragraph is an off-hand trial-balloon, not something the campaign is seriously considering. Still, it does sound like they're de-emphasizing Pennsylvania a bit, which strikes me as a bad idea. For one thing, it's Obama's only hope of wrapping up the nomination before the convention (or, at least, before the last primary). If Obama wins there, it's over for Hillary.
More importantly, I think uncommitted superdelegates want to see a good showing in Pennsylvania before supporting Obama. If I'm a superdelegate, the biggest question I have about him is whether he can win working-class whites in states like Pennsylvania, Ohio, and Michigan--two of which any Democrat has to carry in November. (And don't tell me he did well with working-class whites in Wisconsin. That's true, but the upper Midwest is different from the Rust Belt.) If Obama can't make it close in Pennsylvania--say, five-to-seven points or fewer--I'd start to worry about his viability as a nominee.
For obvious reasons, the Obama campaign has been heavily focused on pledged delegates. But as this piece in yesterday's Washington Post makes clear, a lot of superdelegates feel free to consider other things if the margin stays where it is. One of those things is clearly going to be viability in general-election swing states.
Having said all that, Obama campaign manager David Plouffe did say on his conference call Saturday that the campaign is going to contest Pennsylvania aggressively. So maybe you shouldn't take that first WaPo piece as the final word on their thinking.