"More than one-third of this bill is dedicated to providing tax relief for middle-class families, cutting taxes for 95 percent of American workers," said Senate Majority Leader Harry Reid at a Capitol news conference where he was joined by moderates from both parties whose support is essential for the legislation's final passage.
House Speaker Nancy Pelosi, D-Calif., Reid's partner in negotiations over more than 24 hours, initially withheld her approval for more than two hours in a dispute over federal funding for school construction. She said the delay had been worth it: "We had to make sure the investment in education" was in the bill.
Earlier Wednesday, Evening News anchor Katie Couric asked Pelosi if she had been too partisan during the process, but the speaker defended the House version of the stimulus package that passed without one Republican vote.
"We have strong philosophical difference in the Congress," . "This isn't inner party bickering, this is major difference of opinion on philosophy, on how our country should go forward. We reject the failed Bush administration economic policies which got us where we are today. The proposals that the Republicans put forth were more of the same. We will not go back."
Obama, who campaigned energetically for the measure, welcomed the agreement in a written statement that said it would "save or create more than 3.5 million jobs and get our economy back on track."
The emerging legislation is at the core of Obama's economic recovery program, and includes help for victims of the recession in the form of expanded unemployment benefits, food stamps, health coverage and more, as well as billions for states that face the prospect of making deep cuts in school aid and other programs.
Another provision will mean a one-time payment of $250 for millions of beneficiaries who receive Social Security, Supplemental Security Income and veterans pensions and disability, according to officials.
The measure also preserves Obama's signature tax cut - a break for millions of lower and middle income taxpayers. Wage-earners who don't make enough to pay income taxes would get a reduction in the Social Security and Medicare taxes they pay.
The president also won money for two other administration priorities - information technology in health care, and "green jobs" to make buildings more energy-efficient and reduce the nation's reliance on foreign oil.
The bill "will be the beginning of the turnaround for the American economy," predicted Sen. Joseph Lieberman, the independent from Connecticut.
But embittered Republican leaders said the deal is exactly the wrong prescription for the economy, reports CBS News correspondent Chip Reid.
"I'm very disappointed," said House Minority Leader John Boehner, R-Ohio. "It appears they made a bad bill worse."
The events capped a frenzied 24-plus hours that began at midday Tuesday when the Senate approved its original version of the bill on a party-line vote of 61-37. Reid, Pelosi and White House Chief of Staff Rahm Emanuel plunged into a series of meetings designed to produce agreement in time for Obama to sign the bill by mid-month.
Pelosi was conspicuously absent from Wednesday's news conference in which members of the Senate announced the agreement. Moments later, Reid arrived in her office, and the two talked by phone with Emanuel, according to officials who spoke on condition of anonymity.
Officials had said previously that one of the final issues to be settled was money for school modernization, a priority for Pelosi as well as Obama and one on which they differed with Collins and other moderates whose votes will be essential for final Senate approval.
Originally, Pelosi and House Democrats wanted a new program dedicated to school construction, but Collins held firm against that. In the end, the agreement added money to a State Stabilization Fund, with the additional provision that governors may use some of the money for modernizing school buildings but not building new ones.
There also was last-minute disagreement about a House proposal that could direct education funds to schools even if a state's governor didn't approve, they said, a squabble that one official said related principally to South Carolina.
Stocks moved higher in the moments after Reid stepped to the microphone just outside the Senate chamber. The Dow Jones industrials, which plunged 382 points on Tuesday, rose 51 points for the day.
Obama has been contending daily that the plan is essential to avoid turning what is already the worst economic crisis in a generation into a catastrophe.
As if to underscore the urgency, he said a few hours before the agreement was announced that machinery giant Caterpillar Inc. plans to rescind some of the 22,000 layoffs the firm recently announced - once the stimulus is signed into law.
Public support for the stimulus may be growing. A new USA Today-Gallup poll put backing at 59 percent this week, up from 52 percent in early January.
Working to accommodate the new, lower overall limit of the bill, negotiators effectively wiped out a Senate-passed provision for a new $15,000 tax credit to defray the cost of buying a home, these officials said. The agreement would allow taxpayers to deduct the sales tax paid on new car purchases, but not the interest on loans for the same vehicles.
With numerous demands for the funds in the bill, lawmakers worked to satisfy competing demands.
A Senate-passed provision to give $10 billion to the National Institutes of Health for research - a favorite of both Sen. Tom Harkin, D-Iowa, and Specter, appeared likely to survive.