The measure also is designed to help stabilize markets, in part by making credit more easily available amid rising defaults and falling home values.

The bill permanently increases to $625,500 the size of home loans in high-cost areas that the government-sponsored mortgage companies Fannie Mae and Freddie Mac can buy and that the FHA can insure. It would otherwise have reverted to $417,000 for Fannie and Freddie and $362,790 for the FHA by the end of the year.

The White House sought to focus attention on parts of the legislation aimed at calming markets. Those include the offer of a temporary but unlimited government line of credit for troubled Fannie Mae and Freddie Mac. The Treasury Department gains power, until the end of 2009, to lend them emergency money or buy their stock.

This is considered crucial because investor fears about the health of the companies, which buy or guarantee about half of the nation's mortgage loans.

An overhaul of the Depression-era FHA also was requested by Bush. So, too, was the provision to keep homeowners from making overly risky mortgage choices by requiring lenders to show how high a borrower's payment could get under the terms of his mortgage. It provides $180 million in preforeclosure counseling.

Democratic leaders added an $800 billion increase, to $10.6 trillion, in the statutory limit on the national debt.

The House passed the bill a week ago. Senators voted on Saturday to send it to the president. The votes were supported by many Republicans, particularly those from areas hit hardest by housing woes.

Through the process, Bush did not like what he saw emerging from Congress and said he would veto it. At first, he opposed the foreclosure rescue through the FHA as an overly cumbersome bailout. Later, though, his veto threat was focused almost entirely on the $3.9 billion in neighborhood grants, which he said would encourage lenders to foreclose rather than work with borrowers.