John Edwards quit the race for the presidency yesterday, prompting a scramble by Hillary Clinton and Barack Obama for support that could tilt the balance in a see-saw contest where the Democratic nominee is now certain to be a woman or an African American.

In a speech in New Orleans, where he had announced his candidacy 13 months ago, Mr Edwards said: “It’s time for me to step aside so that history can blaze its path.”

Aides acknowledged that he had struggled to be heard against Mrs Clinton and Mr Obama, whose bids to break through barriers of race and gender “always ensured they would be celebrity candidates”.

Even so, Mr Edwards had still hoped to be kingmaker, picking up enough votes in the big state elections next week to broker the nomination at the Democratic presidential convention in August.

In recent days rumours have circulated that his staff were working without pay as Mr Obama and Mrs Clinton started picking off some of his rich donors. There have also been questions about the absence from the campaign trail of his wife, Elizabeth, who discovered that her breast cancer had returned last year.

Sources close to the family insisted that her health was not the reason for the decision to end what has been a five-year quest by Mr Edwards for the White House. His previous run ended with him being picked as John Kerry’s vice-presidential running-mate in 2004. This year, after a narrow second place in Iowa, he finished third in all subsequent elections including Saturday’s primary in South Carolina, the state where he was born.

Mr Edwards performed consistently well among sections of voters such as white working class men, winning about 10 per cent of the 500 convention delegates awarded so far. They will now be free to vote for either Mrs Clinton or Mr Obama.

His campaign said that he will not be endorsing either of his rivals immediately. Instead, Mr Edwards said that he had received pledges from Mrs Clinton and Mr Obama to carry on his fight against poverty. Speaking in front of a small group of supporters, he described the battle to improve conditions for America’s poor as “the cause of my life”.

Mr Obama praised Mr Edwards and his wife yesterday, saying that they had “given voice to the voiceless and hope to the struggling, even when it wasn’t popular to do”.

Mrs Clinton expressed similar sentiments, promising to make poverty a central theme in the campaign ahead “and, I hope, my presidency”. She is particularly looking to pick up backing from some of the big unions that previously sided with Mr Edwards.

Although she has been frequently attacked by him as a symbol of the “status quo”, he unexpectedly came to her aid in a television debate this month — after which the two candidates held a private 20-minute meeting.

Well-placed sources say that Mr Edwards is seeking a senior post, possibly that of attorney-general, in return for any endorsement. The Clinton camp has downplayed suggestions that it is ready to cut such a deal.

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