BARACK Obama captured the Democratic presidential nomination today, capping a rapid rise from political obscurity to become the first African-American to lead a major US party into a race for the White House.
Rival Hillary Clinton, a former first lady who entered the race 17 months ago as a heavy favourite, did not concede to Senator Obama and said she would consult with party leaders and supporters to determine her next move.
A surge of support from uncommitted delegates helped give Senator Obama the 2118 votes he needed to clinch the nomination and defeat Senator Clinton.
"Tonight, we mark the end of one historic journey with the beginning of another," Senator Obama told a cheering victory celebration in St Paul, Minnesota, at the site of the Republican convention in September.
"Tonight, I can stand before you and say that I will be the Democratic nominee for President of the United States."
Senator Obama's win over Senator Clinton, projected by US networks, came in one of the closest and longest nomination fights in recent US political history.
Five months of voting concluded tonight with votes in Montana, won by Senator Obama, and South Dakota, won by Senator Clinton.
Senator Clinton, who would have been the first woman nominee in US political history, won more than 1900 delegates over the course of the campaign.
She told New York members of Congress she would be open to becoming Senator Obama's vice presidential running mate, and her backers began to turn up the pressure on Senator Obama to pick her as his No. 2.
Senator Clinton congratulated Senator Obama after he clinched the nomination, and told a cheering crowd of supporters in New York City that she would work for party unity. But she did not concede.
"This has been a long campaign and I will make no decisions tonight," she said.
"In the coming days I'll be consulting with supporters and party leaders to determine how to move forward with the best interests of our party and my country guiding my way."
Senator McCain held a rally in Louisiana to kick off the race against Senator Obama. He sought to distance himself from Mr Bush and questioned Senator Obama's judgment and his willingness to put aside partisan interests.
"He is an impressive man, who makes a great first impression," Senator McCain said of Senator Obama.
"But he hasn't been willing to make the tough calls, to challenge his party, to risk criticism from his supporters to bring real change to Washington. I have."
Senator Obama questioned the extent of Senator McCain's independence and tied him to Mr Bush.
"While John McCain can legitimately tout moments of independence from his party in the past, such independence has not been the hallmark of his presidential campaign," he said.
"There are many words to describe John McCain's attempt to pass off his embrace of George Bush's policies as bipartisan and new. But change is not one of them."
Senator Obama, 46, is serving his first term in the US Senate from Illinois and would be the fifth-youngest president in history. He was an Illinois state senator when he burst on the national scene with a well received keynote speech at the 2004 Democratic convention.
Senator Obama's campaign had urged the last 150 or so undecided superdelegates to make their endorsement before the voting ended, so the delegates he wins in the two states voting today could allow him to clinch the Democratic race.
A steady flow of superdelegates complied, making their announcements throughout the day.
Senator Obama lavished praise on Senator Clinton after beating her.
"Senator Hillary Clinton has made history in this campaign not just because she's a woman who has done what no woman has done before, but because she's a leader who inspires millions of Americans," he said in his prepared text.
"Our party and our country are better off because of her, and I am a better candidate for having had the honour to compete with Hillary Rodham Clinton," he said.
Senator Clinton and her campaign have sent mixed signals over the last two days about how long she would stay in a presidential race that she began as a heavy favourite.
During the conference call with New York politicians today, she was asked about running as the No. 2 to Senator Obama and said she was open to the idea.
"She said she would do whatever is necessary in order to make certain that we win, and serving as vice president would be one of the things she would be willing to do," Representative Charles Rangel of New York, a Clinton supporter who was on the conference call, told Reuters.