Obama: "This is our moment"

WASHINGTON — With a split decision in the final two primaries and a flurry of superdelegate endorsements, Sen. Barack Obama sealed the Democratic presidential nomination Tuesday night after a grueling, history-making campaign that will make him the first African American to head a major-party ticket.

Before a chanting, cheering audience in St. Paul, Minn., the first-term Illinois senator savored what once seemed an unlikely outcome to the Democratic race against Sen. Hillary Rodham Clinton. He now faces another hard-fought battle, against Sen. John McCain, the presumptive Republican candidate.

"Tonight we mark the end of one historic journey with the beginning of another — a journey that will bring a new and better day to America," Obama said. "... This is our moment. This is our time. Our time to turn the page on the policies of the past."

Clinton, who waged a fierce campaign to become the first female nominee for president, spoke shortly before Obama at a rally in New York. Amid questions about when or whether she would quit the race, she declared: "This has been a long campaign, and I will be making no decisions tonight."

Earlier in the day, however, she for the first time expressed interest in being Obama's vice-presidential running mate, should he make the offer.

Obama's success marked a milestone for the nation — a sign of the racial progress that has taken place in the span of the senator's lifetime. But the nomination battle also revealed a racial schism within the Democratic Party and potential resistance to a black candidate in parts of the country.

His victory was notable not simply for its historic importance, but also because it marked a rejection, albeit by the narrowest of margins, of a candidate who represented the most powerful family in Democratic politics. Clinton's defeat seemed almost inconceivable little more than six months ago.

In the last two primaries, Obama won Montana but lost to Clinton in South Dakota, a continuation of the seesaw battle the two waged from the first caucuses in Iowa in January. They fought the most closely contested Democratic nomination battle in the modern era and split the party into two almost equal coalitions.

But with the help of superdelegates who declared their allegiance to Obama throughout Tuesday, he easily crossed the threshold of 2,118 delegates needed to secure the nomination as polls closed in Montana and South Dakota.

During his speech, Obama offered praise to his rival. "She has made history not just because she's a woman who has done what no woman has done before, but because she is a leader who inspires millions of Americans with her strength, her courage and her commitment to the causes that brought us here tonight," he said.

Obama still faces a sizable job of uniting his party. Clinton has pledged to help, but she signaled at her rally that she will do so on her timetable.

"You know, I understand that a lot of people are asking, 'What does Hillary want? What does she want?' " Clinton said. She then ticked off a list that included ending the Iraq war, improving the economy and providing universal health care. But in a clear statement aimed at Obama, she added, "I want the nearly 18 million Americans who voted for me to be respected, to be heard and no longer to be invisible."

The last day of the primary-caucus season provided a fitting conclusion to the long nomination battle, a day of extraordinary drama, frenzied speculation and fast-changing events. Obama's campaign worked furiously to pressure uncommitted superdelegates to endorse him, Clinton's campaign struggled to provide her with time to exit on her terms, and the media breathlessly sought to keep pace.

Tuesday began with an unexpected Associated Press report that said Clinton would use her rally Tuesday night to concede. Campaign Chairman Terry McAuliffe immediately went on CNN to deny the report, and the campaign soon issued a terse statement: "The AP story is incorrect. Sen. Clinton will not concede the nomination this evening."

Clinton fought a rear-guard action, with campaign officials pleading with superdelegates and party leaders to give her the dignity of a graceful exit and a rally in which she could celebrate her long campaign rather than concede.

Senate Majority Leader Harry Reid had exhorted a group of uncommitted senators Monday to hold off their declarations until today, and he repeated that plea publicly Tuesday. "Senator Clinton needs to be left alone. ... Let this week work its course," Reid told reporters.

The only remaining question was when — not if — Clinton would step aside. Some advisers, including former chief strategist Mark Penn, reportedly urged her to consider all options, other than quitting outright. Others counseled her to consider her legacy.

Then, in the middle of the afternoon, a new report surfaced about Clinton's interest in the vice presidency. The prospect of a Democratic "dream ticket" has circulated for months, but Clinton always has deflected questions. She embraced the idea Tuesday, in a call with supporters in the New York congressional delegation.

The vice presidency was raised by Rep. Nydia Velazquez, D-N.Y., who said she had implored Clinton to think about the passionate support her candidacy has received from Latino voters.

"She said if she was asked, she would consider it," Velazquez said. "She said, 'Look, I will do whatever it takes to defeat McCain in November.' "

Obama officials were braced for chaos as well Tuesday, hopeful but never certain that the promised superdelegate commitments would materialize. Although more than 150 superdelegates remained up for grabs as of Tuesday morning, Obama aides cautioned that many were unattainable in the short term, having resolved for political reasons to never declare a preference.

"It's not a bottomless pit," one senior Obama adviser said of the superdelegate pool.

By midafternoon, the outcome remained so uncertain that the style and focus of Obama's victory speech was in flux. But one superdelegate after another — some even to the surprise of the Obama campaign — declared support for the Illinois senator, leaving him tantalizingly short of the 2,118 even before polls closed.

The Associated Press declared in the afternoon that Obama had secured enough delegates to win the nomination, although some were still-private endorsements.

Elected to the Senate in 2004 after eight years as an Illinois state senator, Obama, son of a black Kenyan father and a white American mother, accomplished something few thought possible when he launched his candidacy in February 2007.

Clinton seemingly held all the advantages, including a vast network of fundraisers, a web of political supporters in virtually every state, and the allure of being able to restore to power a family that had given Democrats control of the White House for eight years under her husband.

Obama's victory — and Clinton's unexpected third-place finish — in the Iowa caucuses in January upended those expectations and set the candidates on an epic struggle that continued until the polls closed Tuesday night.

The Associated Press contributed to this report.