Recriminations — and speculation — have already begun in the wake of Hillary’s unexpected win in New Hampshire last night. The debate centers on why the polls were so wrong. David Kuo and Andrew Sullivan (among others) suggested that it might be the so-called Bradley Effect in which white support for black candidates is lower at the ballot box than in polling. However, as a friend pointed out to me last night (and as Matthew Yglesias also noted), the polls came close to predicting Obama’s support. They were just way too low on Hillary. So where did the additional votes come from? There are some indications that it was a surge of previously undecided voters, which would be surprising because she is, in effect, the quasi-incumbent in the race, and undecideds usually break heavily against the incumbent.

PS: There’s already a search on to find “moments” and “events” that explain the outcome (particularly the debate or Hillary choking up), but I think it’s going to be hard to establish that those made the difference.

Update 1/9 9:53 AM: The Washington Post has a good rundown of the various explanations for what happened and the available evidence for them. The short answer: It’s unclear.