Washington ? The government’s bold new plan to stem the foreclosure crisis aims to succeed where previous efforts have fallen flat. Yet just as before, the odds are long, and many struggling borrowers won’t qualify.

In theory, the effort unveiled Friday would help millions of troubled homeowners who owe more on their mortgages than their homes are worth, or who are jobless and need a break on their payments.

But it depends on cooperation from investors and bankers, many of whom have been locked in disputes over whether to reduce the debt owed by homeowners.

And just like the bank bailouts, this rescue plan poses risks. If it doesn’t slow the wave of foreclosures or if home prices nosedive, the tentative recovery in the housing market could fizzle.

A foreclosed house is shown Feb. 19 in East Palo Alto, Calif. After months of criticism that it hasn’t done enough to prevent foreclosures, the Obama administration is announcing a plan to reduce the amount some troubled borrowers owe on their home loans.

The Obama administration says the plan will help stabilize the real estate market by keeping many borrowers out of foreclosure. If it succeeds, the plan would limit damage to the overall economy.

The new effort is designed to help two groups:

• Borrowers who owe more on their loans than their houses are worth. More than 15 million homeowners fall into this category, according to Moody’s Analytics. About 10 million of them owe at least 20 percent more than their house’s current value.

Their mortgage companies can cut the total amount they owe, or they can refinance into loans backed by the Federal Housing Administration. FHA will get $14 billion in incentive money from the federal bailout fund.

• Unemployed borrowers. People receiving unemployment benefits would have their mortgage payments cut to no more than 31 percent of their monthly income for three to six months.

That’s intended to give homeowners more time to find a job. Once they do, they may qualify for a loan modification that would permanently reduce their payments under the administration’s existing $75 billion loan modification program.

The plan aims to help 3 to 4 million borrowers avoid foreclosure — the same target the administration tried to reach with its original plan last year. Even with the changes, the effort will likely prevent no more than 1.5 million foreclosures, estimates Mark Zandi, chief economist at Moody’s Analytics.