“After much study, I have concluded that Fannie Mae and Freddie Mac’s adoption of HAMP PRA [the government's Home Affordable Modification Program Principal Reduction Alternative] would not make a meaningful improvement in reducing foreclosures in a cost effective way for taxpayers,” DeMarco wrote in a letter to the chairman and ranking member of the Senate Committee on banking, Housing and Urban Affairs.

DeMarco concludes that the program presents the risk of more losses to taxpayers, not to mention operational challenges to the GSE’s. He cites moral hazard, suggesting that as many as 19,000 borrowers who are current on their mortgages could strategically default in order to qualify for debt forgiveness. Even more significant, he goes on, could be long-term consequences for mortgage credit availability.

“Fundamentally, principal forgiveness rewrites a contract in a way that other loan modification programs do not. Forgiving debt owed pursuant to a lawful, valid contract risks creating a longer-term view by investors that the mortgage contract is less secure than ever before,” writes DeMarco in the letter to lawmakers.

Treasury Secretary Timothy Geithner responded immediately in a letter to DeMarco:

“I do not believe it is the best decision for the country, because, as we have discussed many times, the use of targeted principal reduction by the GSEs would provide much needed help to a significant number of troubled homeowners, help repair the nation’s housing market, and result in a net benefit to taxpayers.”

A study of the program by Treasury’s Michael Stegman showed that mortgage modifications that included principal reduction had a far lower re-default rate than those without the debt forgiveness.

“Fannie Mae’s analysis suggests that using principal reduction to reduce the loan-to-value- (LTV) ratio not only increases a borrower’s ability to pay, but for these selected borrowers, it also increases the likelihood that they will continue to pay,” writes Stegman in the analysis.

The FHFA estimates that up to 500,000 Fannie and Freddie borrowers could have been eligible for principal reduction. The Treasury’s current program pays lenders large incentives to write down loan balances, using unspent money from the $700 billion TARP (Troubled Asset Relief Program). But FHFA says despite a positive financial benefit to Fannie and Freddie, it is really just a transfer of taxpayer funds, adding “to the over $188 billion in taxpayer support the Enterprises have already received.”

Some lawmakers, however, may not be done fighting yet. Several have been pushing for more action to help homeowners, and the heat is on with the election less than 100 days away.

“It is incomprehensible that Mr. DeMarco would reject the chance to save up to a billion dollars in taxpayer funds while helping nearly half a million homeowners stay in their homes,” said Rep. Elijah Cummings (D-MD) in a statement. “He should immediately withdraw this reckless and misguided letter and start following the law Congress passed.”