"For every day we wait or point fingers or drag our feet, more Americans will lose their jobs. More families will lose their savings. More dreams will be deferred and denied," Obama said. "And our nation will sink deeper into a crisis that, at some point, we may not be able to reverse."

The speech today marks the start of the formal campaign to move through Congress a stimulus package that Obama today portrayed in broad strokes as an effort to "retrofit America" -- rebuilding infrastructure while also investing in alternative energy, modernizing schools and extending broadband Internet service to rural areas.

In his speech, Obama blamed the current situation on "profound irresponsibility" -- from money centers like Wall Street to power centers like Washington -- and confronted the critics of his plan directly. He acknowledged both the staggering cost of his proposals and the enormous debt it will impose on future generations. To assuage those concerns, Obama pledges "an unprecedented effort to eliminate unwise and unnecessary spending."

He conceded what skeptics have already said: that the government has already spent a lot of money to turn around the economy with little apparent result.

"We haven't yet seen that translate into more jobs or higher incomes or renewed confidence in our economy," he said.

But, he added, "that's why the American Recovery and Reinvestment Plan won't just throw money at our problems -- we'll invest in what works. The true test of policies we'll pursue won't be whether they're Democratic or Republican ideas . . . but whether they create jobs, grow our economy, and put the American Dream within reach of the American people."

Obama did not unveil the plan itself today. In comments this week, he said that his staff and members of Congress were continuing to work out the final size of the proposal and its details.

House Speaker Nancy Pelosi (D-Calif.) told reporters today that House committees will consider the bill the week of Jan. 19 and she plans to hold a House vote during the last week of January. She said that she has instructed the House leadership team to "think differently" because Democrats now have a larger majority in Congress and control the White House.

Now we have arrived. We have a big, strong, 80-vote majority," she said, explaining it's more important than ever to get things right rather than just passing them quickly.

Under this new timeline, a delay of several weeks from the original timeframe, the Senate would not take up the legislation until the first week of February. Any differences between the two chambers' stimulus plans would require a House-Senate conference committee to reconcile the differences after that, and then the compromise legislation would go back to both chambers. That could put the final passage into mid or late February.

Senate Minority Leader Mitch McConnell (R-Ky.) and House Minority Leader John Boehner, at a press conference after Obama's speech, said they agreed with the president-elect's diagnosis of the perils faced by the economic recession, but they continued to question parts of the plan.

Boehner said the deficit makes it imperative to route out spending in the plan that does not serve the immediate purpose of stimulating the economy, warning that too much spending would wreak long-term havoc. "We can't do one without the other," he said.

But the GOP leaders continued to compliment Obama's approach to dealing with the minority. "It's clear to me, listening to the new president, he wants to include Republican ideas," McConnell said in the LBJ Room off the Senate floor, where Monday afternoon Obama gathered Democratic and Republican leaders to preview the plan.

In his speech today, Obama was gloomy about the country's prospects if they wait too long.

"I don't believe it's too late to change course, but it will be if we don't take dramatic action as soon as possible," he said. "If nothing is done, this recession could linger for years. The unemployment rate could reach double digits. Our economy could fall $1 trillion short of its full capacity, which translates into more than $12,000 in lost income for a family of four.

"We could lose a generation of potential and promise, as more young Americans are forced to forgo dreams of college or the chance to train for the jobs of the future. And our nation could lose the competitive edge that has served as a foundation for our strength and standing in the world."