The issue has polarized Congress. Republicans, who led efforts to rein in Fannie Mae and Freddie Mac before those companies ran into trouble, are now seeking to bridle the F.H.A. Many Democrats insist the F.H.A. is playing a vital role in the housing market, which is only just starting to stabilize.

“F.H.A. has stepped into the void left by the private market,” Representative Maxine Waters, Democrat from California, said at the hearing. “Let’s be clear; without F.H.A., there would be no mortgage market right now.”

That was the case for Bernadine Shimon. Like many Americans, Ms. Shimon has recently been through some rough times. She lost a house to foreclosure, declared bankruptcy, got divorced and is now a single mother, teaching high school English in a Denver suburb.

She wanted a house but no lender would touch her. The Federal Housing Administration was more obliging. With the F.H.A. insuring her mortgage, Ms. Shimon was able to buy a $134,000 fixer-upper in August.

“The government gave me another chance,” she said.

The government is giving as many people as it possibly can the chance to buy a house or, if they are in financial difficulty, refinance it. The F.H.A. is insuring about 6,000 loans a day, four times the amount in 2006. Its portfolio is growing so fast that even F.H.A. backers express amazement.

For decades it was an article of faith that helping people of limited means like Ms. Shimon get a house was good for the new owner, good for the neighborhood and good for American capitalism. Then came the housing bust, which demonstrated that when lenders allowed people to buy houses they ultimately could not afford, it hurt the parties  while putting the economy itself in a tailspin.

In the aftermath of the crash, there is wide divergence on how easy, or how hard, it should be to become a homeowner. Skittish lenders are asking for 20 percent down, which few prospective borrowers have to spare. As a result, private lending has dwindled.