WASHINGTON -- History may remember President Barack Obama as the first black to sit in the White House. But success in his term will depend on his accomplishments rather than on the color of his skin.

He takes office with friendlier majorities in Congress than any chief executive since Lyndon Johnson and confronts economic challenges unrivaled since the era of Franklin Delano Roosevelt.

Rising unemployment, a crippled financial lending system, millions without health care and an economy dependent on foreign oil top the agenda at home. Two wars -- one he has vowed to end, the other to wage -- confront him overseas.

More fundamentally, he told the country Tuesday in his inaugural address, "Starting today, we must pick ourselves up, dust ourselves off and begin again the work of remaking America."

Partially because of America's racial history, Obama's inauguration sparked enormous excitement, and he begins his presidency with a larger reservoir of good will than might otherwise be the case. But like the new president and his aides, even those who stood with Martin Luther King Jr. and then preceded Obama into politics understand that will not be enough.

"This is a victory for democracy, for all Americans who see their hopes and dreams in Barack Obama, who now feel that they have a voice," Rep. James Clyburn, the highest-ranking black in Congress, said in an Inauguration Day statement.

"But after the inaugural celebration ends, I caution the American people to have patience. We face many great challenges that took more than 100 days to create, and will take more than 100 days to rectify," added the South Carolina Democrat.

Obama, 47, projects optimism about the future.

Despite eroded national confidence, he said in his speech, "Our capacity remain undiminished." He urged the nation to choose "hope over fear, unity of purpose over conflict and discord."

The Democratic majorities in Congress are jubilant about the prospect of an Obama presidency, a welcome change for them after the past two years spent struggling with President Bush. He won most of the big political battles, but they won last November's elections, gaining seats in both the House and Senate.

"So we are ready. Democrats have arrived," Speaker Nancy Pelosi, D-Calif., said at a news conference two days after the new Congress convened. "We are ready to lead, prepared to govern."

Pelosi, Senate Majority Leader Harry Reid and fellow Democrats are moving quickly to implement Obama's economic recovery plan. Even before he took office, he won the release of the second half of the $700 billion financial industry bailout that passed Congress last fall. An $825 billion economic stimulus bill is making its way to his desk, with an estimated delivery time of mid-February.

Congressional Democrats leave their own stamp on the measure, a process to be repeated over and over in the president's term. That reflects a healthy tension between two branches of government but is not to be confused with opposition.

Republicans face the first of many decisions as they settle into their new role.

In the Senate, talk of bill-killing filibusters is scarce so far. The GOP now holds only 41 of the 100 seats, with the Minnesota election yet to be settled.

In the House as well as in the Senate, Republicans in safe seats will feel relatively free to oppose the new president. Others will be more inclined to support his program.

Obama's stated goal as he takes office is to expand the latter group as much as possible.

He quietly made it known he was prepared to attend the closed-door weekly lunch held by GOP senators on the same day as last's week's meeting with Democrats. He was asked to wait until after the inauguration.

On his final night before moving into the office, Obama attended a dinner in honor of Sen. John McCain of Arizona, his opponent in last fall's campaign. Pursuing a common purpose rather than political advantage "is built into the very content of his character," Obama said of the man he ran against.

There was an echo of King in that. In the most famous speech of his life, the civil rights leader said a generation ago he hoped his own children could be judged not "by the color of their skin but by the content of their character."

In his inaugural speech, Obama referred to his heritage as "a man whose father less than 60 years ago might not have been served at a local restaurant ..."

But President Obama's horizon is far broader than that.

"That we are in the midst of a crisis is now well understood," he said.