WASHINGTON — Amid a continuing mortgage meltdown across the nation, Congress has begun efforts to revive a controversial housing program to provide down payments for low- and moderate-income families.

The program was killed late last year by the Bush administration and Congress due to concerns that its default rate was too high — two to three times higher than standard mortgages, according to one government estimate.

But supporters of the program, which over the past decade helped more than a million Americans buy a home, say its demise has deepened and extended the economic crisis by preventing a significant pool of buyers from entering the market.

The controversy goes to the heart of the debate over how to revive and stabilize the housing market .

"Tens of thousands of families are sitting on the sidelines, employed people who can't move into home ownership," said Scott Syphax, who pioneered the concept of the down-payment program.

Rep. Al Green, D-Texas, a member of the House subcommittee on housing and community opportunity, has offered a House bill to renew the program.

"We are not talking about a program that taxpayers have to subsidize," Green said. "We can handle any defaults within the program. These loans are solid."

If subprime loans with no income verification and negative amortization represented one risky extreme of low-income lending during the housing bubble, then the down-payment assistance program was somewhere on the other side of the scale, proponents say.

The program was designed to help working-class families that could afford to pay their monthly mortgages but could not save enough for the 3 percent down payment required by a federally backed loan.

For example, Eric Jones, a letter carrier in Sacramento, Calif., was a lifelong renter who could never quite afford a down payment on a home.

Last summer, Jones, along with his wife and two sons, moved into an almost new, $208,000 home in Sacramento with help from the down-payment program. Jones has made his mortgage payments and even shifted to a biweekly payment schedule that will shorten his 30-year loan.

"There is no way I would want to lose my home and go back to renting," he said. "It gives me a sense of pride. It makes me feel more a part of American society."

Under the program, down-payment money did not come from the government, but a nonprofit middle man, such as Syphax's Sacramento-based Nehemiah Corp. of America, which grew to handle about 40 percent of the transactions.

The nonprofit would send money for the down payment to an escrow agent, who would get the money to the seller. After the deal closed, the seller would reimburse the nonprofit the amount of the down payment. Sellers could recoup that money by increasing their price, or simply take the loss in exchange for getting a buyer with a federally backed loan.

If the buyer continued making mortgage payments, the deal cost the government nothing, although some critics complained that the program artificially drove up the price of homes because sellers wanted to recover the money they provided for the down payment.

But if buyers defaulted, the government had to pay off the guaranteed loan provided by the Federal Housing Administration.