WASHINGTON -- Standing before more than 1 million people who clamored to see the nation's first African-American president sworn in, President Barack Hussein Obama yesterday urged them to turn away from "our collective failure to make hard choices and prepare the nation for a new age."

Mr. Obama's speech following his oath of office echoed the words and accomplishments of several members of the select group who have taken that oath before him.

Mr. Obama has often invoked the example of his Illinois predecessor, Abraham Lincoln. His campaign announcement just short of two years ago, at the old state Capitol in Springfield, Ill., was one example. Yesterday was another.

In his first inaugural address, Lincoln called upon his countrymen to follow "the better angels of our nature." In the most famous speech in American history, the Gettysburg Address, Mr. Lincoln said his nation had been "dedicated to the proposition that all men are created equal."

Mr. Obama opened his administration with this declaration: "The time has come to reaffirm our enduring spirit; 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."

Mr. Obama spoke on a cold day under a blue sky, clear but for scattered patches of light cirrus clouds. The noontime sun, low in the winter sky, was on his left as he faced a crowd stretching from the West Front of the Capitol far down the national Mall to the Lincoln Memorial.

He called for a new era of responsibility rooted in the ideals and struggles of the nation's history.

In Franklin Delano Roosevelt's first inaugural speech, he had warned, "The only thing we have to fear is fear itself."

Mr. Obama expressed confidence that his listeners would meet that test as well, declaring, "We gather because we have chosen hope over fear, unity of purpose over conflict and discord."

And in a soaring closing passage, the new president quoted the words of the man who would be the first president, written in a dark moment amid the Revolutionary War: "?'Let it be told to the future world … that, in the depth of winter, when nothing but hope and virtue could survive, … that the city and the country, alarmed at one common danger, came forth to meet [it].'?"

"America," Mr. Obama said, "in the face of our common dangers, in this winter of our hardship, let us remember these timeless words. With hope and virtue, let us brave once more the icy currents and endure what storms may come.

"Let it be said by our children's children that when we were tested, we refused to let this journey end, that we did not turn back, nor did we falter; and with eyes fixed on the horizon and God's grace upon us, we carried forth that great gift of freedom and delivered it safely to future generations."

Conservative evangelist Rick Warren, whose selection to deliver an invocation caused controversy among some of Mr. Obama's liberal supporters, characterized the selection of the first African-American president as "a hinge-point of history," underscoring that with this: "We know today that Dr. King and a great cloud of witnesses are shouting in heaven."

Mr. Obama was more low-key in his allusions to the racial milestone his election represents. He united the struggles of black Americans with those of all citizens of an immigrant nation, as he said: "For us, they packed up their few worldly possessions and traveled across oceans in search of a new life. For us, they toiled in sweatshops and settled the West; endured the lash of the whip and plowed the hard earth."

In a city still legally segregated during the lifetimes of many of his listeners, Mr. Obama said, "This is the meaning of our liberty and our creed -- why men and women and children of every race and every faith can join in celebration across this magnificent mall, and why a man whose father less than 60 years ago might not have been served at a local restaurant can now stand before you to take a most sacred oath."

Early in his address, Mr. Obama offered words of praise and gratitude for the man who would head home to Texas before the inaugural parade began. But other passages suggested a clear rejection of the policies and mores of the administration of George W. Bush.

"As for our common defense, we reject as false the choice between our safety and our ideals," Mr. Obama said after a campaign in which he had portrayed the Bush years as a time of erosion of civil liberties and pledged to shut down the Guantanamo Bay prison base that the sitting administration had used to detain scores of terror suspects.

"Our Founding Fathers, faced with perils we can scarcely imagine, drafted a charter to assure the rule of law and the rights of man, a charter expanded by the blood of generations. Those ideals still light the world, and we will not give them up for expedience's sake," he said yesterday to loud applause.

"And so to all other peoples and governments who are watching today, from the grandest capitals to the small village where my father was born: know that America is a friend of each nation and every man, woman and child who seeks a future of peace and dignity, and that we are ready to lead once more."

On the economy, Mr. Obama offered a broader indictment of the recent past that tacitly included his predecessor, but extended to the overall climate of hyper-partisan years shaped by politicians of both parties. "Our economy is badly weakened, a consequence of greed and irresponsibility on the part of some, but also our collective failure to make hard choices and prepare the nation for a new age," he said.

"On this day," he added, "we come to proclaim an end to the petty grievances and false promises, the recriminations and worn-out dogmas that for far too long have strangled our politics."

In the face of a worldwide economic crisis, Mr. Obama promised "bold and swift action."

"Now, there are some who question the scale of our ambitions -- who suggest that our system cannot tolerate too many big plans," he said after reciting a litany of domestic needs in energy, infrastructure and other areas. "Their memories are short. For they have forgotten what this country has already done; what free men and women can achieve when imagination is joined to common purpose, and necessity to courage.

"What the cynics fail to understand is that the ground has shifted beneath them -- that the stale political arguments that have consumed us for so long no longer apply. The question we ask today is not whether our government is too big or too small, but whether it works."

Two hours earlier, the Obamas and the Bushes had shared coffee at the White House before they headed to a ceremony attended by the other living past presidents, Jimmy Carter, George H.W. Bush and Bill Clinton. The newly ex-President Bush left the Capitol grounds on Marine One shortly after the rite of transition.

As his helicopter headed down the Mall and circled the White House and the Washington Monument, scattered catcalls and boos from the dispersing crowd were at odds with the mood of amity characterizing the Capitol's unmistakably upbeat mood.

Mr. Obama was sworn in by Chief Justice John Roberts, who reversed words when he fed Mr. Obama the phrases of the traditional oath, causing both men to stumble in the recitation.

The Illinois Democrat used his full name, Barack Hussein Obama, in contrast to a campaign in which he seldom mentioned it -- in some measure because of the false but persistent assertions that he was a Muslim, rather than a Christian.

In his speech, the figure who spent part of his early years in Indonesia, attending a Jakarta grade school in the world's largest Muslim nation, reached out to the broader Muslim community.

"To the Muslim world, we seek a new way forward, based on mutual interest and mutual respect," he said. "To those leaders around the globe who seek to sow conflict, or blame their society's ills on the West -- know that your people will judge you on what you can build, not what you destroy.

"To those who cling to power through corruption and deceit and the silencing of dissent, know that you are on the wrong side of history; but that we will extend a hand if you are willing to unclench your fist."

In addition to the throngs on the Mall, hundreds of thousands more people staked out spots along Pennsylvania Avenue to watch the parade that followed the Obamas' luncheon with members of Congress and other dignitaries in the Capitol's Statuary Hall.

That lunch was marred, however, as veteran Sen. Edward Kennedy, D-Mass., who has been diagnosed with brain cancer, suffered an apparent seizure and had to be carried out for treatment at a nearby hospital. His symptoms were later described by a doctor as the result of fatigue.

Whatever the precise numbers, the crowd was clearly a record for an inaugural event. But through the crowded, often-slow trials of transportation and security checks, these celebrants displayed almost uniform good cheer and patience.

As they led the traditional parade down Pennsylvania Avenue, the new president and first lady twice got out of their limousine and walked, basking in the cheers of the thousands of spectators who had braved the cold and tight security to get a glimpse of the nation's new leader.

Mr. Obama's swearing-in was preceded by that of Vice President Joseph R. Biden, who was to go on to celebrate with other native Pennsylvanians and partiers from his Delaware home in one of the many balls that would fill the Washington night. Mr. Biden did not give a speech after his swearing-in. The 30-some words of his oath may have been his shortest public utterance on record.