The margin in the New Hampshire primary was razor-thin. But she clearly beat Barack Obama among core Democratic voters, the very bloc that will grow in influence as the nomination fight continues in the coming weeks.

Strip away the independents who made up about four in 10 participants in Tuesday’s Democratic primary, thanks to the state’s open-balloting rules, and Clinton outpaced Obama 45 per cent to 34 per cent, according to an exit poll conducted for a media consortium.

Moreover, she beat the Illinois senator among women — a crucial group for her and one that she lost in last week’s Iowa caucuses — and among lower-income households and older voters.

“This is an amazing comeback story for her over the course of a relatively few days,” said Mark Mellman, a Democratic strategist who advised John F Kerry’s 2004 presidential campaign.

If her advantage among Democrats holds true in the flurry of primaries set for February 5, Clinton could regain the traction that seemed lost when last week’s defeat in Iowa ended her yearlong reign as the Democratic front-runner.

Only registered Democrats can take part in a number of the February 5 contests. Non-Democrats are not welcome. For example, in voting in Connecticut, Arizona and in Clinton’s home state of New York, potential strongholds for Clinton that each control more nomination delegates than the relative handful from Iowa, New Hampshire and other earlier states.

Another major prize that day is California, where unaffiliated voters will be permitted to participate in the Democratic primary. But some strategists believe California’s Latino voters could boost Clinton, who is more popular in that group than Obama.

All told, more than 2,000 delegates will be decided that day, enough to seal the nomination. And by proving her strength, Clinton on Tuesday probably succeeded in calming skittish donors and supporters who had begun to wonder if she could even last until next month’s contests.

The exit polls, conducted by Edison/Mitofsky for a media consortium, surveyed 1,955 Democratic primary voters. The survey found that Clinton, who spoke on Monday of shattering the “highest and tallest glass ceiling in our country” by becoming the first female President, won 46 per cent of women’s votes, compared to 34 per cent for Obama.

She also defeated Obama among voters older than 40 and won more than a third of voters in a key part of Obama’s base, those in their mid-20s and 30s.

Tuesday’s results should help to further shape the Democratic race as a two-person contest between Obama and Clinton.

Third-place finisher John Edwards has vowed to campaign through the summer, apparently hoping that one of the front-runners would stumble and leave the former North Carolina senator as the only challenger. Should he drop out or fizzle, it is not clear which of his chief rivals would benefit more, with Clinton likely to draw union members and lower-income people who had been drawn to Edwards.

Obama, who would be the country’s first black President, is expected to win the January 26 Democratic primary in South Carolina in which African Americans will make up at least half of the electorate.

Clinton is considered competitive in Nevada, which holds its caucuses on January 19. Moreover, although the influential culinary workers union had been expected to endorse Obama on Tuesday, strategists believed the group may now hold back.

Still, before Clinton can truly declare herself the “Comeback Kid”, it was clear Tuesday that Clinton has some repair work to do.

The exit polling suggested that some of her long-held advantages had evaporated in New Hampshire. No longer was Clinton viewed as the most likely candidate to beat a Republican. In the poll, 44 per cent said Obama was more likely to win the November election, compared to 35 per cent who said that of Clinton.

And Obama, as he did in Iowa, proved his ability to attract new voters. One in five voters Tuesday said it was their first time participating in a primary, and a big plurality of those backed Obama.

Clinton made clear that she intends to transform her campaign, declaring that she “found my own voice” while campaigning in the state. Still unclear is whether that will be a voice for the kind of “change” that spawned Obama’s rise, or a voice of “experience” that is the basis for Clinton’s campaign until her Iowa loss.