Liz Glenn, a community planning official in Baltimore County, Md., said the grants "would enable us to acquire and rehab more homes and offer them at an affordable price."

The Treasury Department would gain power to extend the government-sponsored mortgage companies an unlimited line of credit and to buy an unspecified amount of their stock, if necessary. The two companies, chartered by Congress, back or own $5 trillion in mortgages — nearly half the nation's total.

Sen. Richard C. Shelby of Alabama, the top Republican on the Senate Banking, Housing and Urban Affairs Committee, said Bush's turnabout reflected political reality.

"They looked at the Hill, they counted some votes and they see there's pretty broad support for this," said Shelby, his party's lead negotiator.

He and Sen. Christopher J. Dodd, the committee chairman, said they would push for swift approval of the measure without any changes.

"We'll be anxious to move this product along," said Dodd, D-Conn.

Conservatives led by Sen. Jim DeMint, R-S.C., were threatening to slow the measure unless Democrats allowed a vote on barring Fannie Mae and Freddie Mac from lobbying and making campaign contributions. Senators' objections could delay enactment of the measure until next week.

Congressional analysts estimate that a government rescue of the mortgage giants could cost $25 billion, but they predict there is a better than even chance it will not be needed.

The bill would let the Federal Housing Administration back $300 billion in new loans so an estimated 400,000 homeowners who cannot afford their house payments could try to escape foreclosure by refinancing into safer, more affordable mortgages. Lenders would have to agree to take a substantial loss on the existing loans, and in return, they would walk away with at least some payoff and avoid the often-costly foreclosure process.

"The industry really has to step up and use it," said Bruce Dorpalen, director of housing counseling for Acorn Housing Corp., a nonprofit housing group based in Philadelphia.

The plan also creates a new regulator with tighter controls for Fannie Mae and Freddie Mac and modernizes the agency. It includes about $15 billion in housing tax breaks, including a credit of up to $7,500 for first-time buyers, and increases the statutory limit on the national debt by $800 billion, to $10.6 trillion.

Lawmakers abandoned efforts to place conditions on any Fannie and Freddie rescue, but the bill hands the new regulator approval power over the pay packages of executives at the companies.