John Edwards ended his campaign today in the same way he started it — by standing with the people who are too often left behind and nearly always left out of our national debate," Clinton said.

Obama, too, praised Edwards and his wife. At a rally in Denver, he said the couple has "always believed deeply that two Americas can become one, and that our country can rally around this common purpose," Obama said. "So while his campaign may have ended, this cause lives on for all of us who still believe that we can achieve that dream of one America."

Edwards, trudging through mud toward a Habitat for Humanity House he was to help work on, told reporters he would meet again with Clinton and Obama before deciding whether to make an endorsement. He set no timetable for deciding whether to endorse either candidate.

The impact of Edwards' decision will be felt in one week's time, when Democrats hold primaries and caucuses across 22 states, with 1,681 delegates at stake.

Four in 10 Edwards supporters said their second choice in the race is Clinton, while a quarter prefer Obama, according to an Associated Press-Yahoo poll conducted late this month.

Edwards amassed 56 national convention delegates, most of whom will be free to support either Obama or Clinton.

As expected, Edwards said he was suspending his campaign rather than ending it, but aides said that was simply legal terminology so that he can continue to receive federal matching funds for his campaign donations.

An immediate impact of Edwards' withdrawal will be six additional delegates for Obama, giving him a total of 187, and four more for Clinton, giving her 253. A total of 2,025 delegates are needed to secure the Democratic nomination.

Edwards won 26 delegates in the Iowa, New Hampshire and South Carolina contests. Under party rules, 10 of those delegates will be automatically dispersed among Obama and Clinton, based on their vote totals in those respective contests. The remaining 16 remain pledged to Edwards, meaning his campaign will have a say in naming them.

Three superdelegates — mainly party and elected officials who automatically attend the convention and can support whomever they choose — had already switched from Edwards to Obama before news of Edwards' withdrawal from the race.

Edwards waged a spirited top-tier campaign against the two better-funded rivals, even as he dealt with the stunning blow of his wife's recurring cancer diagnosis. In a dramatic news conference last March, the couple announced that the breast cancer that she thought she had beaten had returned, but they would continue the campaign.

Their decision sparked a debate about family duty and public service. But Elizabeth Edwards remained a forceful advocate for her husband, and she was often surrounded at campaign events by well-wishers and emotional survivors cheering her on.