Hillary Rodham Clinton's hopes of becoming the nation's first female president suffered a significant blow, and her days as the Democrats' national front-runner are over for now after her third-place finish. The New York senator faces a rough slog in coming weeks unless she manages to bounce back Tuesday in the New Hampshire primary, in which she could be an underdog.
A record Democratic caucus turnout - including a large number of younger voters and liberals - responded enthusiastically to Obama's inspirational candidacy and to his call for a new style of politics in Washington. His supporters outnumbered Clinton's older, largely female backers in a generational split that, caucus-night polling showed, heralded the arrival of a new breed of Democratic voter: more independent politically and ready for government to act on problems such as giving affordable health care to millions who lack medical coverage.
Obama now has a realistic chance to become the first African-American nominated by a major party. He appears well-positioned to defeat Clinton in New Hampshire and in the first Southern primary, later this month, in South Carolina, where black voters are a dominant force.
"Hope, hope is what led me here today, with a father from Kenya, a mother from Kansas and a story that could only happen in the United States of America," the freshman senator from Illinois told a delirious crowd, labeling his caucus victory as a "defining moment in history."
Clinton, conceding defeat for the first time, said she was "so ready for this campaign." She described herself as "a candidate who will be able to go the distance," signaling her intention to dig in for a long, tough fight.
Unless she rebounds in New Hampshire, she could be forced to devise a fallback strategy centered on the 22 states that vote Feb. 5, including New York, New Jersey and California.
John Edwards, who edged Clinton out for second place, said the clear message of the Iowa results "is the status quo lost and change won." He described the Iowa results as a bipartisan repudiation of "two candidates who thought their money would make them inevitable," referring to Clinton and Republican Mitt Romney.
But the former North Carolina senator is likely to have a hard time keeping his candidacy going for long against his two better-funded rivals.
Reflecting the new reality of the Democratic contest, Sens. Christopher J. Dodd of Connecticut and Joseph R. Biden Jr. of Delaware, who got about 1 percent of the caucus vote between them, pulled out of the race.
On the Republican side, Huckabee is no longer a joke as a presidential contender.
Iowa proved "that people are really more important than the purse, and what a great lesson for America to learn," the former Arkansas governor said in claiming victory. "Tonight, I hope we will forever change the way Americans look at their political system and how we elect presidents."
A historic tide of evangelical votes - three out of five Republicans identified themselves in a caucus-night poll as born-again or evangelical Christians - swamped the party establishment in Iowa and vaulted another gifted politician from the tiny town of Hope, Ark., into national contention.
Huckabee's triumph did not make him the front-runner, and the Republican contest remains muddled nationally.
In New Hampshire, Huckabee's social conservatism and his campaign's religious tone are hurting him. Instead, he is counting on Arizona Sen. John McCain to eliminate Romney from serious contention there.
The former Massachusetts governor will be under extreme pressure to rack up a save for his campaign in neighboring New Hampshire, where McCain has overtaken him in recent polling.
Speaking to supporters in Manchester last night, McCain congratulated Huckabee on his victory.
It proves that "you can't buy an election in Iowa," said McCain. Negative campaigns "don't work there and they don't work here in New Hampshire."
Romney, the rescuer of the 2002 Winter Olympics, has outspent his rivals in both states, waging a negative ad barrage against Huckabee in Iowa and McCain in New Hampshire.
Huckabee, an ordained Baptist minister, seasons his message with a healthy dose of populist spirit. In New Hampshire, where economic conservatives rule, he is casting himself as a tax-cutter and calling for a national sales tax to replace the income tax.
In recent days, he has crystallized the image he hopes to project, describing himself as a candidate who reminds people "more of the guy they work with rather than the guy that laid them off."
His easygoing manner and ability to think on his feet pulled him out of the lower tier of candidates last fall. In Iowa, Huckabee overcame a huge financial disadvantage against Romney, who has put at least $17 million of his own money into his campaign and has outspent Huckabee by nearly 20-to-1.
Huckabee's victory was also a turning point for Iowa Republicans, whose badly divided party reflects a similar split nationally and who now face new problems in a state that President Bush narrowly won in 2004.
An informal coalition of evangelical Christians, home-schoolers and social conservative activists rewrote the rules of the Iowa caucuses, which had decreed that an intense focus on organization was the only way to win. Romney had the best organization money could buy, but it was no match for Huckabee's crusaders.
On Tuesday, New Hampshire will hold the first primary of 2008. Just four days of post-Iowa campaigning - less time than ever before - will give the unsuccessful candidates little time to rebound. For the same reason, the winning surge in popularity that victors traditionally ride out of Iowa will have less time to fade.
In particular, strategists will be trying to determine the impact that Iowa will have on independent voters in New Hampshire, who can pick either a Republican or a Democratic primary ballot.
McCain benefited from independent votes when he upset Bush in New Hampshire eight years ago. But this time, many are being drawn to Obama's campaign, polls have shown.
If McCain is able to repeat his 2000 primary victory, he and Huckabee would face off in South Carolina, where religious conservatives are a potent force in Republican primaries.
Fred Thompson, who was in a close third-place contest with McCain in Iowa, has almost no support in New Hampshire. The former Tennessee senator is likely to face increasing pressure to quit the race and back McCain, as he did in firstname.lastname@example.org