With his history-making election behind him, Barack Obama was moving ahead with his transition on Wednesday as he prepared to confront the daunting challenges that he will have to face as president in just 76 days, with two wars and the gravest economic crisis to afflict the country since the Great Depression.


The three co-leaders of Mr. Obama’s transition team are expected to be announced sometime on Wednesday — John D. Podesta, the former Clinton chief of staff; Valerie Jarrett, a longtime Obama adviser; and Pete Rouse, Mr. Obama’s Senate chief of staff.

Rep. Rahm Emmanuel of Illinois, a former Clinton aide and close friend of Mr. Obama, is considered the leading candidate to be White House chief of staff.

Mr. Obama got in a morning workout on Wednesday, but was expected mostly to be behind closed doors, meeting with members of his staff. Campaign workers at his Chicago headquarters were told to take the morning off and not to show up until noon. Many, of course, are scrambling to sort out their own futures, hoping for roles in the new administration.

Dan Pfeiffer, who served as the Obama campaign’s communications director, is to become the communications director for the transition, with Stephanie Cutter, a senior Obama adviser and former aide to Sen. Edward M. Kennedy, serving as spokeswoman for the transition, according to Democrats close to the process.

President Bush offered his congratulations to Mr. Obama in public remarks on Wednesday morning and pledged to cooperate fully with Mr. Obama’s transition team, promising to keep the President-elect informed of important decisions.

“No matter how they cast their ballots, all Americans can be proud of the history that was made yesterday,” President Bush said. “The long campaign has now ended,” he added. “We move forward as a nation.”

The White House has already set up a transition office for Mr. Obama’s team in downtown Washington. And FBI officials have been conducting background checks on a list of people provided by the Obama campaign, as well as Senator John McCain’s staff, so they could be granted interim security clearances on Wednesday, administration officials have said.

In contrast, Republican leaders began on Wednesday what will likely be a lengthy re-evaluation of their brand, as Democrats hope to shape a long-term realignment of the electoral map. Not only did Mr. Obama capture the presidency, but he led his party to sharp gains in Congress. This puts Democrats in control of the House, the Senate and the White House for the first time since 1995, when Bill Clinton was in office.

“Certainly, we have to examine this,” said Rep. Kay Bailey Hutchinson, a Texas Republican, on CNN on Wednesday. “We have to listen to what the people are saying if we’re going to be a forceful voice.”

Mr. Obama’s supporters continued to revel on Wednesday in the moment, reflecting on its symbolism amid the nation’s fraught racial history.

Colin Powell, the former secretary of state in the Bush administration who endorsed Mr. Obama, became emotional on Wednesday in an interview with CNN from Hong Kong, confessing that he and his family had wept when the networks declared Mr. Obama the victor.

“I have to share in the pride that Americans have now for the fact America did this,” said Mr. Powell, one of the country’s most prominent black leaders.

Mr. Powell added that he believed this was a time for “deep introspection on the part of the Republican Party.”

“They have to take a very realistic look at themselves — we do — I am a Republican, and see where we went wrong, where we aren’t attaching ourselves to the hopes, dreams and ambitions of the American people,” he said.

But even as they celebrated, Mr. Obama’s supporters quickly shifted to sober reflections of what lay ahead.

“We’re in deep trouble,” said Rep. John Lewis, a Georgia Democrat and leader in the civil rights movement, on the Today show on NBC.

“We’ve got to get our economy out of the ditch, end the war in Iraq and bring our young men and women home, provide health care for all our citizens,” Mr. Lewis said. “And he’s going to call on us, I believe, to sacrifice. We all must give up something.”

The election of Mr. Obama amounted to a national catharsis — a repudiation of a historically unpopular Republican president and his economic and foreign policies, and an embrace of Mr. Obama’s call for a change in the direction and the tone of the country.

But it was also an exorcism of sorts of some of the most divisive episodes of the country’s history with regards to African Americans. It was a moment unthinkable even just two years ago.

Mr. Obama, 47, a first-term senator from Illinois, defeated Mr. McCain of Arizona, 72, a former prisoner of war who was making his second bid for the presidency.

To the very end, Mr. McCain’s campaign was eclipsed by an opponent who was nothing short of a phenomenon, drawing huge crowds epitomized by the tens of thousands of people who turned out to hear Mr. Obama’s victory speech in Grant Park in Chicago.

Mr. McCain also fought the headwinds of a relentlessly hostile political environment, weighted down with the baggage left to him by President Bush and an economic collapse that took place in the middle of the general election campaign.

“If there is anyone out there who still doubts that America is a place where all things are possible, who still wonders if the dream of our founders is alive in our time, who still questions the power of our democracy, tonight is your answer,” said Mr. Obama, standing before a huge wooden lectern with a row of American flags at his back, casting his eyes to a crowd that stretched far into the Chicago night.

“It’s been a long time coming,” the president-elect added, “but tonight, because of what we did on this date in this election at this defining moment, change has come to America.”

Peter Baker contributed reporting from New York and Jeff Zeleny from Chicago.