Barack Obama declared victory Tuesday night at a raucous rally at the Xcel Energy Center in downtown St. Paul.

"Tonight, after fifty-four hard-fought contests, our primary season has finally come to an end," he told thousands of supporters who had jammed the arena to witness an historic moment as Obama became the first black candidate in the nation's history to become a major party presidential nominee. The crowd of 17,000 exploded in an ear-splitting roar.

"Tonight, I can stand before you and say that I will be the Democratic nominee for president of the United States," he said, setting off another roar even louder and longer.

An additional 15,000 supporters watched the speech on a big screen outside the arena, according to fire officials.

In prepared remarks, Obama praised his vanquished rival, Hillary Rodham Clinton, and took direct aim at John McCain, the Republican he will face in November.

"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," he said, "but because she's a leader who inspires millions."

Of McCain, Obama said that he respects "his many accomplishments, even if he chooses to deny mine. My differences with him are not personal; they are with the policies he has proposed in this campaign ... 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."

Directing his words beyond the hall to a national audience, he declared: "America, this is our moment."

With overwhelming numbers gathering outside the hall, the doors were opened early.

Among the throng was James Burrage, 18, of Minneapolis, who will vote for the first time in November, thrilled that the face of the candidate he might support will be the same color as his own.

"That's definitely one of the major reasons I'm here," said Burrage, who had stood in line since just past noon. "There is the historic nature of what's happening. There has not been a black man running for president like this before."

"It's a huge thing," said Rep. Keith Ellison, D-Minn., one of Obama's earliest supporters. "Our country is a country that for 2 1/2 centuries had Africans as chattel slavery and a century after that had Jim Crow," Ellison said Tuesday morning on Minnesota Public Radio. "America as a country keeps on getting better."

The Clinton campaign

Clinton's campaign spent much of Tuesday tamping down reports that she planned to drop out of the race. Speaking to supporters Tuesday night, she said she would make no immediate decision and asked backers to advise her on what her next step should be.

Earlier Tuesday, Clinton said for the first time that she would be interested in becoming Obama's vice presidential running mate. "I am open to it," she said during a conference call with other members of Congress from New York.

McCain anointed Obama as the Democratic standard bearer while delivering his kickoff general election speech in New Orleans. McCain said Obama will be "a formidable" opponent.

Polls show a close race between Obama and McCain. A Gallup Poll released Tuesday showed McCain with the support of 46 percent of registered voters nationwide to Obama's 45 percent.

The Obama campaign's choice of the Xcel Center for its triumphal rally was a calculated poke in the eye of Republicans, who will stage their national convention in the arena in September.

"The other side will come here in September and offer a very different set of policies and positions, and that is a debate I look forward to," Obama said. "It is a debate the American people deserve. But what you don't deserve is another election that's governed by fear and innuendo and division."

WOW outside the Xcel

Even before Obama flew from his home in Chicago to the Twin Cities, the Republican Party criticized him, with Gov. Tim Pawlenty doing the honors.

He said Obama "is someone who continues to demonstrate a lack of experience and judgment" and belittled his résumé as including "a professor of some type and a community organizer."

Pawlenty dismissed Obama as "a gifted orator and speaker, but being able to read a teleprompter is not preparation to be president."

The scene outside the Xcel Tuesday had the air of a rock concert. There were few signs of dissent but plentiful signs of capitalism, as vendors hawked Obama t-shirts, hats and buttons.

The crowd was eclectic: card-playing college kids ordering pizza from Cosseta's alongside seasoned political hands such as Sidney and Ray Faricy, two long-time St. Paul political insiders and active Obama supporters. Sidney and three of her friends, all 72, proclaimed themselves a new group: WOW, which stands for white old women (for Obama).

The idea of seeing Obama in person also inspired Tina Carstens, 32, of Brooklyn Park, who said she recognized the bitterness the campaign between Obama and Clinton had created among some women.

"But there's none of that in any of my circle of friends," she said.

Obama's triumph was fashioned on prodigious fundraising, meticulous grass-roots organizing and an overarching theme of change.

With her husband's two White House terms as a backdrop, Clinton campaigned for months as the all-but-inevitable candidate of experience.

But after a year on the campaign trail, Obama won the kickoff Iowa caucuses on Jan. 3, and the freshman senator became something of an overnight political phenomenon.

Tuesday was Obama's fourth visit to Minnesota, where he scored a decisive win on Feb. 5, beating Clinton by a 2-1 margin in the state's precinct caucuses. That was one of nearly two dozen contests held on Super Tuesday, a day Obama battled Clinton to a draw. Soon after, he began to open a lead she could never close.

Outside the Xcel, Joe Forbes said he's seen the political wind shift. A vendor for www.shoppolitical.com. Forbes was hawking Obama hats and playing cards. "You can guess who the jokers are," he said. A day earlier, Forbes was in Sioux Falls, S.D., for a Clinton rally. The goods were not moving. "There was a crowd, but they were really disenfranchised. You think they got the sense that this was the end?" he asked.

Staff writer Kevin Duchschere and the Associated Press contributed to this report. Bob von Sternberg • 612-673-7184 Mark Brunswick • 651-222-1636

THE ROAD AHEAD

Opening bell of America's championship political bout has rung. A5