WASHINGTON – His name etched in history as America’s first black president-elect, Barack Obama turned Wednesday from the jubilation of victory to the sobering challenge of leading a nation worried about economic crisis, two unfinished wars and global uncertainty.

“The road ahead will be long. Our climb will be steep,” Obama cautioned.

Young and charismatic but with little experience on the national level, Obama smashed through racial barriers and easily defeated Republican John McCain to become the first African-American destined to sit in the Oval Office, America’s 44th president. He was the first Democrat to receive more than 50 percent of the popular vote since Jimmy Carter in 1976.

“It’s been a long time coming, but tonight, because of what we did on this date in this election at this defining moment, change has come to America,” Obama told a victory rally of 125,000 people jammed into Chicago’s Grant Park.

After an improbable journey that started for Obama 21 months ago and drew a record-shattering $700 million to his campaign account alone, Obama scored an Electoral College landslide that redrew America’s political map. He won states that reliably voted Republican in presidential elections, like Indiana and Virginia, which hadn’t supported the Democratic candidate in 44 years. Ohio and Florida, key to President Bush’s twin victories, also went for Obama, as did Pennsylvania, which McCain had deemed crucial for his election hopes.

With most U.S. precincts tallied, the popular vote was 52.3 percent for Obama and 46.4 percent for McCain. But the count in the Electoral College was lopsided – 349 to 147 in Obama’s favor as of early Wednesday, with three states still to be decided. Those were North Carolina, Georgia and Missouri.

With just 76 days until the inauguration, Obama is expected to move quickly to begin assembling a White House staff and selecting Cabinet nominees. Campaign officials said Illinois Rep. Rahm Emanuel was the front-runner to be Obama’s chief of staff. The advisers spoke on a condition of anonymity because the announcement had not yet been made.

With these moves and many others to come upon him quickly, Obama planned a low-key, everyman day-after in his hometown of Chicago. The president-elect was taking his two young daughters to school, and then heading to the gym, with little else on his schedule.

The nation awakened to the new reality at daybreak, a short night after millions witnessed Obama’s election – an event so rare it could not be called a once-in-a-century happening. Prominent black leaders wept unabashedly in public, rejoicing in the elevation of one of their own – at long last.

The Rev. Jesse Jackson, who had made two White House bids himself, said on ABC’s “Good Morning America” that the tears streaming down his face upon Obama’s victory were about his father and grandmother and “those who paved the fights. And then that Barack’s so majestic.”

“He’s going to call on us, I believe, to sacrifice. We all must give up something,” Rep. John Lewis, a Georgia Democrat and leading player in the civil rights movement with Jackson, said on NBC’s “Today” show.

Speaking from Hong Kong, retired Gen. Colin Powell, the black Republican whose endorsement of Obama symbolized the candidate’s bipartisan reach and bolstered him against charges of inexperience, called the senator’s victory “a very, very historic occasion.” But he also predicted that Obama would be “a president for all America.”

Bush, whose public approval ratings have plummeted in the waning days of his presidency, was mostly behind the scenes in the last weeks of the historic campaign. He called Obama to congratulate him late Tuesday and scheduled a midmorning statement in the White House Rose Garden.

Democrats expanded their majority in both houses of Congress.

In the Senate, Democrats ousted Republicans Elizabeth Dole of North Carolina and John Sununu of New Hampshire and captured seats held by retiring GOP senators in Virginia, New Mexico and Colorado. Still, the GOP blocked a complete rout, holding the Kentucky seat of Senate Minority Leader Mitch McConnell, the Minnesota seat of Norm Coleman, who had been challenged by Democrat Al Franken, and a Mississippi seat once held by Trent Lott – three top Democratic targets.

In the House, with fewer than a dozen races still undecided, Democrats captured Republican-held seats in the Northeast, South and West and were on a path to pick up as many as 20 seats.

When Obama and running mate Joe Biden take their oath of office on Jan. 20, Democrats will control both the White House and Congress for the first time since 1994.

“It is not a mandate for a party or ideology but a mandate for change,” said Senate Majority Leader Harry Reid of Nevada.

House Speaker Nancy Pelosi of California said the American people “have called for a new direction. They have called for change in America.” She scheduled a midday news conference on Capitol Hill Wednesday to elaborate.

Obama faces a staggering list of problems, that he called “the greatest of our lifetime – two wars, a planet in peril, the worst financial crisis in a century.”