If Hillary Clinton was the big winner in New Hampshire on Tuesday night, the biggest losers were the pollsters, almost all of whom had predicted a massive victory for Barack Obama.
Seldom before have so many separate polls got a result so badly wrong, and yesterday morning questions were being asked about the methodology they used.
Among eight leading polls this week, none predicted a victory for Clinton and most said Obama would win by at least eight points, with one poll giving him a 13-point lead.
Most polls are conducted by phone, using a sample of up to 1,000 people. Polling organisations screen respondents to determine who is most likely to vote, usually based on behaviour in previous elections, but most polls admit a margin of error of plus or minus three points.
In New Hampshire, the polls of Republican primary voters were accurate and the Democratic polls were right about all the candidates except Clinton and Obama.
Some commentators yesterday suggested that Obama may have been a casualty of the "Bradley effect", named after former Los Angeles mayor Tom Bradley, an African-American who was ahead in polls for the 1982 Californian gubernatorial election, but unexpectedly lost to his white opponent.
Post-election analysis showed that some white voters who said they were voting for Bradley changed their minds in the polling booth.
However, a closer look at Tuesday's result in New Hampshire shows that the polls came close to estimating Obama's share of the vote correctly. Where they went wrong was in underestimating Clinton's.
What made the difference was the women's vote, 46 per cent of which went to Clinton, while Obama received 34 per cent. Women's turnout was massive, making up 57 per cent of the Democratic electorate and voting by women over 40 was especially high.
In Iowa, only 30 per cent of women voters backed Clinton compared with 35 per cent for Obama, but something happened in the final hours of the New Hampshire campaign to motivate women to come out for Clinton.
Obama's support came from the young - he was very heavily backed by the 18 to 24 age group - and from voters who had attended university.
He also won more independent voters than Clinton, but they did not have the influence that they did in Iowa because many chose to vote in the Republican primary, backing John McCain.
The key moment in persuading women to back Clinton may have come on Monday when the former first lady became tearful when she was asked how she coped with the stress of the campaign.
Marianne Pernold Young (64), a freelance photographer, was one of a small group of women who went to meet Clinton at a coffee shop in the town of Portsmouth on the day before the vote.
Although a lifelong Democrat, Young and the others were undecided at that point in the race.
"It showed us that she is human and manages to still perform in the way she does, and still has a person inside of her. She is a human being. She is not a robot," Young told the Guardian.
But although she was moved by Clinton's display of emotion, it did not influence her vote on polling day. "I was leaning towards Obama and I voted for Obama. It's strange, but he made me cry when I went to see him," she said. "We need new blood."
