Countrywide Financial, once the country’s largest mortgage lender, was charged with fraud during the housing-bubble collapse. (RICK WILKING/REUTERS)

In his July 29 letter, “Stop blaming big banks,” Robert E. Long claimed “we now know” that the mortgage crisis was caused by a lowering of mortgage loan standards by Fannie Mae and Freddie Mac to meet the politically motivated housing goals mandated by the Clinton and George W. Bush administrations. There is nothing new about this hypothesis; it was considered, along with several other explanations, by the members of the Financial Crisis Inquiry Commission, whose report was submitted to the president in January 2011.

Of the 10 members of the commission, only one, Peter J. Wallison, took the extreme position Mr. Long holds. Of the four members appointed by the Republican congressional leadership, three rejected the idea that Fannie Mae and Freddie Mac by themselves caused the crisis, as did the six members appointed by the Democratic leadership.

Jim Taylor, Alexandria