House Democrats doubled down on their ongoing feud with the head of the Federal Housing Finance Agency this week as they demand answers from the GSE regulator about a previously unknown 2010 Fannie Mae pilot program to forgive borrower’s mortgage debt that was shelved due to what Dems say was a philosophical opposition to loan writedowns.In a letter to FHFA Acting Director Edward DeMarco, Reps. Elijah Cummings, D-MD, and John Tierney, D-MA, of the House Committee on Oversight and Reform, accused the agency head of being less than forthright in his response to lawmakers justifying the FHFA’s position against the writedown of underwater GSE mortgages.“The single most significant revelation in your letter to Congress is that, even based on your own questionable assumptions and data, principal reduction programs serve the taxpayer interests even when compared to your preferred alternative of forbearance,” said Cummings and Tierney.