Barack Obama beat Hillary Clinton in the South Carolina Democratic primary Saturday night, after a bitter campaign injected with questions about race and gender.

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"Our time for change has come," Obama told a enthusiastic audience, which interrupted him with chants of, "Race doesn't matter."

"We have the most votes. We have the most delegates. And we have the most diverse coalition of Americans that we have seen in a long, long time," he said. "We are ready to believe again."

"We're up against the conventional thinking that says your ability to lead as president comes from longevity in Washington or proximity to the White House," Obama said. "But we know that real leadership is about candor and judgment and the ability to rally Americans from all walks of life around a common purpose, a higher purpose.

"We're up against decades of bitter partisanship that cause politicians to demonize their opponents instead of coming together to make college affordable or energy cleaner. It's the kind of partisanship where you're not even allowed to say that a Republican had an idea, even if it's one you never agreed with.

"That's the kind of politics that is bad for our party, it is bad for our country, and this is our chance to end it once and for all."

Returns from 95 percent of the state's precincts showed Obama winning 55 percent in the three-way race, Clinton gaining 27 percent and Edwards at 18 percent.

The South Carolina Democratic Party broke its own turnout record in the primary and eclipsed the number of ballots cast by residents in the Republican primary the week before.

More than 509,000 votes had been tabulated in Obama's commanding victory here. The returns easily eclipsed the 280,000 people who voted in the Democratic primary in 2004.

Democratic Party officials characterized the record-breaking vote as a resurgence for a party in the minority in both houses of the Legislature and with only two of eight House and Senate seats in Washington. The only statewide office-holding Democrat in the state is the education superintendent.

The win gives Obama's campaign momentum in the prelude to a Feb. 5 coast-to-coast competition for more than 1,600 Democratic National Convention delegates.

The South Carolina victor also gained an endorsement from Caroline Kennedy, who likened the Illinois senator to her late father, President John F. Kennedy.

"I have never had a president who inspired me the way people tell me that my father inspired them," she wrote on The New York Times op-ed page. "But for the first time, I believe I have found a man who could be that president - and not just for me, but for a new generation of Americans."

Clinton flew to Nashville as the polls closed, and looked ahead. "Now the eyes of the country turn to Tennessee and the other states voting on Feb. 5," she said, adding "millions and millions of Americans are going to have their voices heard."

Edwards finished a distant third, a sharp setback in the state where he was born and scored a primary victory in his first presidential campaign four years ago. Even so, he vowed to remain in the race, his goal, he said, to "give voice to all those whose voices aren't being heard."

How They Voted

About half the voters were black, according to polling place interviews, and four out of five of them supported Obama.

Black women turned out in particularly large numbers. Clinton and Edwards each won roughly 40 percent of the white vote, with about 25 percent going to Obama, the first-term Illinois senator.

Three in four voters said the country is ready to elect a black president, and about the same said the country is ready to elect a woman. Nine in 10 Obama voters said the country is ready for a black president, but fewer Clinton voters said the country is ready.

Nearly all Clinton voters and two-thirds of Obama voters said the country is ready to elect a woman president.

Given three choices, half the voters in Saturday's primary said the economy was the most important issue facing the country -- up from 38 percent in the only other competitive Democratic primary to date, in New Hampshire on Jan. 8. About a quarter picked health care, comparable to New Hampshire. Only about one in five picked Iraq, down from 27 percent in New Hampshire.

The results are from a partial sample of 1,269 voters conducted by Edison Media Research and Mitofsky International in 35 precincts in South Carolina's Democratic primary. The margin of sampling error plus or minus 4 percentage points.

As in New Hampshire, three in four Obama voters said the most important quality in a candidate is that he can bring about needed change. Four in 10 Clinton voters said their priority was that a candidate has the right experience while nearly three in 10 picked change. Edwards scored highest on empathy -- at least half his voters said it was most important that the candidate "cares about people like me." Few voters said the candidate's electability was their top priority.

Asked whether their candidate's positions on issues or leadership and personal qualities were more important to their vote, six in 10 said issues.

Three in four voters said the country is ready to elect a black president and about as many said that about a woman. Somewhat more Clinton voters said the country is not ready to elect a black than Obama voters said the country wasn't ready to elect a female president.

After the contentious Democratic debate Monday night, three in four Obama voters said Clinton had attacked Obama unfairly and slightly fewer than half accused their own candidate of attacking Clinton unfairly.

Two-thirds of Clinton voters said Obama attacked her unfairly and nearly as many said she attacked him unfairly. Edwards voters were more likely than either of the other candidates' supporters to say both Clinton and Obama attacked each other unfairly.

Roughly four out of five voters said they would be satisfied if Clinton or Obama wins the Democratic nomination. Slightly more Clinton voters said they would be dissatisfied with Obama than vice-versa.

Slightly more Obama voters said Clinton would be more likely to be the eventual Democratic nominee than vice-versa.

Obama becomes the first black candidate to win a major party primary election since 1988, when Jesse Jackson won seven Democratic primaries in 1998, including Alabama, the District of Columbia, Georgia, Louisiana, Mississippi, Puerto Rico, South Carolina and Virginia. Jackson also won four caucuses: Delaware, Michigan, South Carolina and Vermont.

Polls opened at 7 a.m. EST and election officials reported no problems with voting machines as there were in last week's GOP primary after one county's electronic machines failed to function properly.