Illinois Sen. Barack Obama solidly defeated New York Sen. Hillary Clinton in Iowa's Democratic caucus on Thursday evening, posing a dramatic challenge to a campaign that has cloaked itself in an air of inevitability. Barack took 38 percent of the vote to former North Carolina senator John Edwards's 30% and Clinton's 29%. In doing so, Obama captured 57% of the under-30 vote, according to CNN. Obama would be the first African-American president and, at 47, one of the youngest ever, if he were to go on to capture the Democratic party nomination and then the White House. Themes of change and hope dominated his campaign, and they were the concepts he focused on in celebrating his win before elated supporters following the caucus. "We are choosing hope over fear... and sending a powerful message that change is coming to America," he told several hundred cheering Iowans, many of them waving "Stand for Change" signs. "You have done what the cynics said we couldn't do." Iowans of all ages and colors turned out for Obama's victory speech, but the crowd was dominated by enthusiastic young supporters. Obama's ability to tap into new voters, both those who only recently became old enough to vote and those who have never come out on caucus night before, was widely viewed as a key to his resounding win. More than 225,000 people turned out for the Democratic caucuses on a freezing Thursday evening, up from 124,000 in 2004. The jump included numerous new party enrollees, many of them former independents and even some Republicans. Unlike primaries, where people vote individually in a process that can take mere minutes, a caucus is a group affair that can last hours. That has traditionally kept all but the most committed members of the parties' bases from coming out. But Obama succeeded in turning out hordes of new voters as well as party stalwarts, and in winning among both groups. His success was easily observable in the caucus at the Valley High School in West Des Moines, where one precinct had a record turnout - 419 this year versus 167 last time. In a cafeteria whose chairs and tables had been rolled back to make room for voters, scores of Iowans congregated in the corner assigned to Obama, infringing on the territory staked out for Clinton and creating overflow crowds. After those present have physically gathered in the area designated for their candidate, the groups self-count to determine a winner; in the case of Obama, supporters took turns counting off like schoolchildren assigned numbers so their teachers can keep track of those present. While Clinton's initial tally came to 87, an Obama supporter could be heard reaching triple digits. "100!" she shouted to cheers, as the audience kept on going, eventually reaching 157. The young faces of the Obama resembled students at a pep rally rooting for their team; they stood in stark contrast to Clinton's camp, which was mostly seated and gray-haired. After the first round of voting, supporters from each side had the chance to win over undecided hold-outs before a second round as backers took turns standing on a cafeteria chair and beseeching voters. While the response for Obama, Edwards and New Mexico Gov. Bill Richardson was enthusiastic, the Clinton surrogate was met with dubious laughter when she tried to press her candidate's case by referring to Clinton's time in the White House. It seemed to go against the grain of other teams' appeals for change on policies ranging from health care to the Iraq war to the climate. "I like the political face Obama has. It's fresh, it's different - it's hope," said Democrat Deb Vranesk. Though she had been undecided until the previous day, Clinton was not on the list of those she had been considering. But despite Vranesk's pleasure at her candidate's victory, she emphasized that the intimate caucus process was "friendly" rather than "hateful or aggressive," though she did refer to those who lobby other voters between balloting rounds as "like piranhas." One white-haired Clinton supporter tried to win over wavering voters with a more appealing tack. "We've got food for you!" she declared. A truly participatory form of democracy, there are few safeguards against counting errors or cheating during the caucuses. The Republican process is a more sedate affair, as voters write down names on scraps of paper in a secret ballot that is then counted as it would be in a classroom electing a member of the student council. At Valley High School, a debate briefly broke out over whether former Arkansas governor Mike Huckabee's supporters had tampered with the ballots by ripping their pieces of paper in half and writing his name down twice. One caucus observer resolved the issue by pointing out, "It would be jagged if someone ripped them." With that the caucus officials went back to tallying the results on a legal pad, finding that former Massachusetts governor Mitt Romney had received 99 votes to Huckabee's 52. Those numbers were in contrast to the statewide results, which gave Huckabee 35% to Romney's 25%. Leaving the Obama post-caucus event, a tall man in a long winter coat stepped into the frigid night air and warmed it with his broad smile. He was one of the few black members of the crowd gathered to celebrate victory in a state comprised almost entirely of white residents. "What a night," he said. "What a night."