Ben Smith makes a great point here. He says Obama's had such a rough stretch lately that it'll be almost impossible for Hillary to spin a single-digit win (my margin, not his) into a victory. Expectations for Obama have fallen through the floor.
Meanwhile, and somewhat counter-intuitively, the polls continue to show progress for him. I'm not sure I believe he's only down five in Pennsylvania, but, boy would he take that now...
I know some readers are probably sick of my psychoanalytical mumbo jumbo, but one thing to keep in mind is that the psychology of the moment almost certainly favors Obama. I've argued that it's really hard for him to land a knockout blow because, while a lot of voters don't want Hillary to win, they don't want her to lose either. Every near-death encounter--New Hampshire and March 4 in particular--seems to net her a bounce.
But it obviously doesn't look like she faces elimination in Pennsylvania on Tuesday. On top of which, she's looking as unsympathetic as she's looked in weeks. So in some respects, the conditions may be ripe for a better-than-expected Obama showing: People can vote for Obama without worrying about killing Hillary, and those who do think they're killing Hillary may actually want to by now.