DES MOINES, Iowa - Sen. Barack Obama of Illinois won Iowa's Democratic caucuses Thursday evening, in a setback for Sen. Hillary Rodham Clinton of New York in the battle for the party's 2008 presidential nomination.

With 80 percent of the precincts reporting, Obama was drawing about 36 percent of the delegates awarded, putting him ahead of Clinton and former senator John Edwards of North Carolina, both of whom were winning about 30 percent of delegates. Multiple news organizations projected Obama would emerge victorious, and Clinton called Obama to congratulate him shortly before 9 p.m. Central time.

After nearly a year of campaigning and tens of millions of dollars spent in the state, Iowa Democrats gathered in schools and churches Thursday night to begin selecting a presidential nominee amid what appeared to be record turnout.

Obama's campaign message of hope and change attracted significant support from first-time caucus attendees, while Clinton focused her campaign tightly on the issue of experience and Edwards looked to ride a wave of populist anger toward Washington to an upset that would put him into the thick of the nominating battle nationally.

The caucuses began at 7 p.m. Central time and first reports indicated huge participation, which in some cases threatened to overwhelm the process. Four years ago, 124,000 Iowans took part in the Democratic caucuses and the early signs Thursday night indicated that this year's number would exceed 200,000. In 2004, about 160 people caucused for Democrats at precinct 211 in West Des Moines. This year, 437 attended.

Obama advisers believed that the bigger the turnout the better he would do, but Clinton's campaign team predicted that it, too, would attract a flood of newcomers to the caucuses, including many older women.

Five other candidates were on the ballot: Sen. Joe Biden of Delaware; Sen. Christopher Dodd of Connecticut; New Mexico Gov. Bill Richardson; Rep. Dennis Kucinich of Ohio and former senator Mike Gravel of Alaska.

Biden, Dodd and Richardson all hoped to confound pollsters and make a surprisingly strong showing, but they knew that a poor result could doom their under-funded candidacies.

Iowa's caucuses represented the leadoff contest in the nomination battle, with the subsequent primaries and caucuses coming in the most compressed calendar in the party's history.

New Hampshire will hold its first-in-the nation primary next Tuesday, with Nevada and South Carolina also scheduled to hold contests this month. The busiest day on the calendar will be Feb. 5, when nearly two dozen states - including many of the biggest in the country - will vote.

Earlier Thursday, the candidates nervously awaited the opening of the caucuses, attending final rallies, giving television interviews, and making telephone calls and last-minute preparations.

Obama's voice was hoarse, but his confidence hours before the caucus was evident. The Illinois senator spent the day doing interviews with news organizations around the state, including a spot with KCZE Radio morning show host Chad Scott in which Obama urged listeners to “get off your couch and make a difference.”

His only public event was a walk through a downtown Des Moines food court. At one point he was asked whether he is an atheist. “I'm a member of the Trinity United Church of Christ,” Obama replied. “Don't read e-mails” (a reference to bogus Internet rumors that Obama is either a Muslim or an atheist).

Karen Ritchie, 67, told Obama: “I've been to every caucus since 1972 and I'm going for you tonight.”

Edwards staged a 36-hour campaign marathon that began on New Year's Day and ended with a concert and rally in Des Moines on Wednesday night. But he was out again on Thursday. He stopped in Des Moines, Iowa City and Cedar Rapids, then, in the hours before the precinct doors opened, he urged supporters to call their friends and to make it to the caucuses on time.

Clinton spent the day with her husband, daughter and mother and a handful of supporters who traveled to Iowa to campaign. Among the lunch guests was Washington D.C. resident Sarah Ehrman, 88, who knew the senator since before she married former president Bill Clinton.

Ehrman recounted driving Hillary Clinton to Arkansas after working on the Watergate committee. “All the way down, I was saying: `Are you nuts? That guy is going to be a country lawyer. He'll never amount to anything.' And she said `I love him.' The rest,” Ehrman said, “is history.”

The former president sought to drive up turnout with last-minute radio interviews in some smaller towns.

Thursday's voting came after the longest, costliest and most hard-fought Democratic campaign in Iowa's history. The three leading candidates spent an estimated $60 million on their campaigns in Iowa, with Clinton and Obama each spending in excess of $20 million, according to campaign officials.

The Iowa campaign began more than a year ago, when former governor Tom Vilsack announced his candidacy for the Democratic nomination in Mount Pleasant, Iowa. He was out of the race within a few months, but by that time, the campaign here was in full swing.

Edwards announced his candidacy on Dec. 28, 2006, in New Orleans and immediately flew to Des Moines for an early evening rally. More than 1,000 people showed up to see him, one of the first signs of the enormous energy and enthusiasm that has greeted Democratic candidates here throughout the past 12 months.

Clinton was the next of the major candidates to arrive, flying into Des Moines on Jan. 26 for a chocolate shake and fries at a diner, a meeting with Iowa Gov. Chet Culver and a dinner with supporters. She began her public campaigning the next day with a rally at East High School in Des Moines and then rolled east through Cedar Rapids and Davenport through the rest of the weekend.

Obama waited until February to formally announce his candidacy. After a speech on the grounds of the Old State Capitol in Springfield, Ill., he turned his attention to Iowa with rallies in Cedar Rapids, Waterloo and Ames.

Clinton began the race in a dominant position nationally but a far shakier standing in Iowa. Bill Clinton had skipped the Iowa caucuses when he first ran for president in deference to Sen. Tom Harkin of Iowa, who was also a candidate that year.

Unlike Edwards, who never stopped campaigning in Iowa after his 2004 campaign, Hillary Clinton did not set foot in the state in 2006 and had no natural network of support to rely on when she announced her campaign. Polls showed that many Iowans, including Democrats, were skeptical about her candidacy and many felt negatively toward her.

Clinton was quickly put on the defensive about the Iraq conflict. In the early stages of the campaign, she was challenged on her 2002 vote for the resolution authorizing the war but resisted calls to apologize for it. Still, her campaign was nervous enough about the potential drag on her candidacy that, when the time came to give a speech outlining her views on how to bring U.S. troops home, she did it in Iowa.

Clinton's campaign was slow to put down firm roots in the state, forcing her advisers to play catch-up with Edwards, who continued visiting after his surprise second-place finish in 2004, and Obama, who hails from next-door Illinois. Even after bringing on longtime Iowa organizer Teresa Vilmain over the summer, Clinton watched her support in the state stall, leaving her trailing as late as the fall.

Clinton regained her footing in December following an endorsement by the Des Moines Register. After attacking Obama's character and attempting to share her biography, she returned to her main theme at the end: strength and experience.

Her husband campaigned vigorously on her behalf, arguing that only she would be qualified to assume the presidency from the start. By the end of the race, Clinton was drawing large and enthusiastic crowds, many of them filled with women eager to see the woman who could become the first female president.

The first Iowa Poll by the Des Moines Register, released last May, showed Edwards leading the Democratic field with 29 percent, and Obama at 23 percent and Clinton at 21 percent.

By October, Clinton had taken the lead in the Iowa Poll, at 29 percent, to 23 percent for Edwards and 22 percent for Obama. Little more than a month later, Obama was narrowly ahead in the survey, although the field was closely bunched. Obama was at 28 percent, Clinton at 25 percent and Edwards at 23 percent.

The final poll by the Register was released on New Year's Eve and showed Obama widening his lead, a finding that was immediately challenged by strategists for the Clinton and Edwards campaigns. That survey put Obama at 32 percent, Clinton at 25 percent and Edwards at 24 percent. -0-