The presidency passed to Democrat Obama from Republican George W. Bush at the stroke of noon, marking one of democracy's greatest gifts: the peaceful transfer of power.
But a stark transfer all the same. In one of the new administration's first acts, Obama ordered federal agencies to halt all pending regulations until further review -- this after Bush's final weeks raised heated debate over rushing new rules into effect on the way out the door.
And even though new White House aides struggled to find offices and work intercoms, an overhauled www.whitehouse.gov Web site was running under Obama's banner within minutes of his swearing-in. "Change has come to America," it declared.
Obama plunges into his new job in earnest on Wednesday after capping inaugural festivities at a national prayer service in the morning, meeting with his economic team and Iraq advisers and welcoming a stream of public visitors into the White House while Congress gives his economic revival plan a going-over and takes up the nomination of Hillary Rodham Clinton to be secretary of state. Her confirmation has been held up for now by Republican concern over the foundation fundraising of her husband, the former president.
The new president had been buoyant and relaxed through the three days of pre-inaugural festivities. But he seemed somber as he stood on the Capitol steps, placed his left hand on the Bible used by Abraham Lincoln and repeated the inaugural oath "to preserve, protect and defend" a Constitution that originally defined blacks as three-fifths of a person. A deafening cheer went up.
"What is required of us now is a new era of responsibility -- a recognition, on the part of every American, that we have duties to ourselves, our nation, and the world, duties that we do not grudgingly accept but rather seize gladly," Obama said. "This is the price and the promise of citizenship."
It was a day of high spirits -- jarred by sudden concern about the health of Sen. Edward M. Kennedy. The legendary Democrat, suffering from brain cancer, and was rushed from a Capitol luncheon in Obama's honor to a hospital. "My prayers are with him and his family," Obama said. Later, fellow Sen. John Kerry of Massachusetts said Kennedy was laughing and joking at the hospital and itching to get back to work.
On the inaugural parade route, Obama and his wife, Michelle, climbed out of the heavily armored presidential limousine and walked a few blocks along famed Pennsylvania Avenue, waving to adoring crowds under the watchful eyes of security agents.
Obama wove a thread of personal responsibility and accountability through his inaugural address, an 18-minute sermon on civic duty. A liberal Democrat proposing billions of dollars in new spending, Obama nonetheless spoke of the limits of government.
"It is the kindness to take in a stranger when the levees break, the selflessness of workers who would rather cut their hours than see a friend lose their job which sees us through our darkest hours," he said. "It is the firefighter's courage to storm a stairway filled with smoke, but also a parent's willingness to nurture a child, that finally decides our fate."
Obama's 10-year-old daughter, Malia, aimed a camera at her father as he spoke. Michelle leaned onto the edge of her seat, body tensed and brow knitted.
"Starting today, we must pick ourselves up, dust ourselves off and begin again the work of remaking America," Obama said.
He placed blame for the recent economic collapse not just on greed and irresponsibility "on the part of some" but also on the inability or unwillingness of everyone to move the country beyond an industrial-based economy -- what he called "our collective failure to make hard choices and prepare the nation for a new age." With that, the 47-year-old former Illinois senator transformed himself -- from a candidate claiming his campaign is about the voters to a president promising to put the nation in the people's hands.
Unlike most predecessors, Obama takes office with his agenda in many ways set for him.