The Federal Housing Finance Agency and other government regulators could “permanently enshrine” Fannie Mae, Freddie Mac and other government housing entities “as the only large-scale source of mortgage credit in our country” if they fail to design a new mortgage rule with care, says one senior Republican senator. Sen. Bob Corker, R-TN, a member of the Senate Banking, Housing and Urban Affairs Committee, in a letter last week urged federal regulators to “simplify and synchronize underwriting standards for new mortgage lending rules to avoid permanently regulating the private sector out of the housing finance business.” Corker, in his letter to the FHFA, Federal Reserve, Department of Housing and Urban Development, and the Securities and Exchange Commission, among other agencies, noted that the proposed, but yet to be finalized, “qualified residential mortgage” rule exempts loans sold to Fannie, Freddie and the Federal Housing Administration.