Poll failure: a boon to Clinton AND Obama?
What's weird about New Hampshire is that Clinton was safely the leader there for months, and by double digits, until right after the Iowa caucuses. Then Obama went from a fourteen point deficit in the New Hampshire polls to something like a four to ten point lead—completely unprecedented. Every major poll had Obama ahead, and even all the campaigns' internal polls—Clinton's included—showed the same thing.
I don't know enough about how polls are taken to explain why this happened. No one seems to know enough, it appears. But from the looks of things, it would appear that Obama got an eleven-point bounce in New Hampshire after Iowa—which is pretty typical. It was probably the sharply increased turnout that made people think that there'd be a colossal break for Obama, but in the end, he got a pretty typical bump there.
I don't know what this means for the next campaigns, but the poll failure gives the impression that Clinton outperformed what's normal instead of seeing a very average dip in her New Hampshire numbers. It's great for Senator Clinton, but only the craziest conspiracy theorist could possibly conclude that her campaign or the media or some entity manufactured this. But it's a fantastic piece of luck for her.
Now Obama needs to move on to Nevada and South Carolina and do well. This hit in New Hampshire might actually help him to manage expectations; after all, if you're seen as inevitable, one or two mistakes could seriously crush you.