Because the housing market collapse helped trigger a credit crisis and the broader economic decline, the president argued, acting "boldly and swiftly" to arrest a coming wave of foreclosures would have positive effects across the economy and benefit every American.

"In the end, all of us are paying a price for this home mortgage crisis," he said. "And all of us will pay an even steeper price if we allow this crisis to deepen, a crisis which is unraveling homeownership, the middle class and the American Dream itself."

Obama presented the plan at a high school outside Phoenix, in a state where roughly one out of every 182 homes faced some stage of foreclosure proceedings last year. The plan aims to help two broad classes of homeowners.

The administration says the program will help as many as 5 million people refinance their mortgages at current low interest rates. This portion aims to help people who are current on their payments and meet other financial criteria, but whose homes have lost so much value that they cannot qualify for conventional refinancing.

In addition, the administration aims to help as many as 4 million homeowners who are at risk of foreclosure because of a spike in an adjustable interest rate, or who have lost a job or otherwise been hurt by the recession. It aims to bring mortgage payments down to 31 percent of a borrower's monthly income.

The housing initiative is shaping up to be the most politically palatable component of Obama's larger plan to fix the economy, which includes the $787 billion stimulus package he signed this week and rescue plans for the financial services sector and the auto industry

Even Republicans who have opposed other parts of Obama's solution were reluctant to be too critical of the housing plan on Wednesday.

Still, the introduction of yet another multi-billion-dollar plan drew a cautious response from some members of Congress, who are already suffering what some have called "bailout fatigue." House Republican leaders sent a letter to Obama posing questions about his housing proposal, opening with a query about how the plan would help "the over 90 percent of homeowners who are playing and paying the rules."

The plan is far more detailed than the bank rescue proposal the administration rolled out last week, which was widely assailed for its vagueness and blamed for an immediate plunge in the stock market.