WASHINGTON -- Rising to face one of the largest gatherings of Americans in history, a solemn Barack Hussein Obama took the oath of office Tuesday as the nation's 44th president, pledging to begin the work of "remaking America" and proclaiming the arrival of "a new era of responsibility."

The 47-year-old son of a Kenyan father and Kansan mother, who became the first African-American president, recalled the nation's civil rights struggle in his inaugural address outside the U.S. Capitol, overlooking the National Mall.

"On this day," he said, "we gather because we have chosen hope over fear, unity of purpose over conflict and discord." He described himself, in a reminder both of his mixed heritage and of the distance the nation has traveled, as "a man whose father less than 60 years ago might not have been served at a local restaurant."

Obama took the presidential oath on the same Bible used to swear in Abraham Lincoln in 1861, as the nation veered toward civil war, two years before the Emancipation Proclamation ended slavery.

Obama's much-anticipated 20-minute address evoked the nation's founding principles of equality.

"The time has come to reaffirm our enduring spirit," he said. "To choose our better history; to carry forward that precious gift, that noble idea, passed on from generation to generation: the God-given promise that all are equal, all are free and all deserve a chance to pursue their full measure of happiness."

Appealing to hope amid two wars and a shattered economy, the new president drew some of his loudest cheers when he said, "Starting today, we must pick ourselves up, dust ourselves off and begin again the work of remaking America."

But amid the calls to action and "a new era of peace," Obama also proclaimed what he called "a new era of responsibility" in which duty to others would claim a larger place. He challenged "some who question the scale of our ambitions" and "cynics [who] fail to understand ... that the ground has shifted beneath them."

In a brief reprise of the postpartisan theme of his campaign, Obama said "the stale political arguments that have consumed us for so long no longer apply."

But in a direct repudiation of the national security policies of outgoing President George W. Bush, who looked on from the stands behind him, Obama rejected "as false the choice between our safety and our ideals."

Rapture in the crowd

Obama spoke before a jubilant crowd of more than 1 million. Standing, jumping, cheering, clapping, shoulder to shoulder, they stretched 2 miles from the Capitol to the Lincoln Memorial.

Among them was Josie Johnson, a retired University of Minnesota professor and longtime African-American community activist who helped organize the Minnesota delegation to the 1963 Civil Rights March on Washington, when Obama was 2 years old. It was there that the Rev. Martin Luther King Jr. delivered his famed "I Have A Dream" speech.

"It was a tearful moment for me," Johnson said of the inauguration. "The dream that Martin Luther King had was fulfilled today."

In keeping with the spirit of the moment, Republicans said that despite their differences with Obama they look forward to finding common ground with the new Democratic administration. Among them was Rep. Michele Bachmann of Minnesota, one of Obama's harshest critics during the campaign. She called the inauguration "a profound day for America and for the American people."

The central event began with an awkward moment, as Obama faltered slightly through the 35-word oath, apparently thrown off by Chief Justice John Roberts, who seemed to scramble the words.

But breaking immediately into a broad smile, the new president was greeted with euphoric chants of "Obama! Obama!" -- as many in the crowd wept, hugged and waved flags amid the neoclassical columns of the federal buildings that face the National Mall.

Among Obama's rapturous followers in the crowd, the celebration took on the mood of a religious revival. "I believe it's a divine appointment from God that this day was to be," said Flora Boles, the daughter of an Arkansas sharecropper. She drove to the ceremony from Lansing, Mich., with a half-dozen family and church members. She said that her late father lived through segregation and that she came to Washington "to represent him."

For some it was a matter of not just witnessing history, but living it.

"It's a lovefest," said Letitia Lee, an artist from Hampton, Va. "You can talk about the idea of unity, but when people actually physically come together and try to do something, change will come."

And there was also the sense that the wider world was watching. "As a black man, I appreciate the step that America has taken," said Haiti native Patrick Gaspard, who drove his family to the inauguration from Montreal.

Challenges ahead

The swearing-in was witnessed by more than 2,000 Minnesotans who obtained tickets through their congressional offices. Among the Minnesota dignitaries was former Vice President Walter Mondale. But given the long security lines, a ticket to the ceremony was no guarantee of actually getting there.

St. Paul native Lora Pollari-Welbes was one who didn't make it, even after a four-hour wait. She ended up listening to the speech on a passerby's radio. "We had a good time anyway," she said. "It was worth every minute of it."

Jean Nusbaum, a Twin Cities anesthesiologist who arrived at the Lincoln Memorial carting her 5-year-old son Alex in a wagon, had walked 4 miles in subfreezing temperatures from her sister's house in Virginia.

"This is the most exciting thing that's happened in my lifetime," she said.

Countless more arrived without tickets and joined the swelling non-ticketed crowds. Among them were Krissy Luoma, Ward Beavers and Dusty Hogenson. They had boarded a bus at the Kwanzaa Community Church in north Minneapolis Monday morning, driving through the night to make time.

"There were so many people, but everyone was in such a good mood," said Luoma, a 25-year-old nightclub hostess from Minneapolis. "I've never been in such a happy crowd before."

Other Minnesotans were there to be part of the pageantry, including 300 members of the Minnesota National Guard's 1st Battalion, 194th Armor (Combined Arms Battalion), who traveled to Washington to provide security.

Also represented were the chairpersons of 11 Minnesota Indian tribes who carried a treaty stick adorned with 11 white bald eagle tail feathers from the University of Minnesota's Raptor Center.

But amid the symbolism, there was also the sense that the journey is not over, Johnson said. "Now it means that we get home and all start working," she said. "There are always new challenges."

Staff writer Mitch Anderson contributed to this report. Kevin Diaz • 202-408-2753