For those looking for a nice summary of issues around Fannie and Freddie, I found this article in the NY Sun pretty informative.
From 1938 to 1968, the secondary mortgage market in the United States was monopolized by the Federal National Mortgage Association (Fannie Mae), which was a government agency during that period. In 1968, to help balance the federal budget, part of Fannie Mae was converted to a private corporation. To provide competition in the secondary mortgage market, and to end Fannie Mae's monopoly, Congress chartered Freddie Mac as a private corporation.
The Emergency Home Finance Act of 1970 created Freddie Mac. The goal was to create a secondary market for conventional mortgages...