"Fannie Mae first ensures that the loans it acquires generally meet its credit quality guidelines and then it securitizes the pool of mortgages. The loans are converted -- or securitized -- into more liquid, flexible instruments. The resulting Fannie Mae MBS carries a guarantee of timely payment of principal and interest to the investor, whether or not there is sufficient cash flow from the underlying group of mortgages. Fannie Mae's obligation under this guaranty is solely Fannie Mae's and is not backed by the full faith and credit of the U.S. government."
Note the source of that quote:
http://www.fanniemae.com/mbs/mbsbasics/market/structure.jhtml?p=Mortgage-Backed+Securities&s=Basics+of+Fannie+Mae+MBS&t=Basics+of+MBS+Market+%26+Pools&q=MBS+StructureApparently Baker knows more than Fannie Mae does about Fannie Mae. In fact, they were early leaders in producing securities based on mortgages. It allowed them to buy up a lot of loans and then sell them in little pieces--which allowed them buy more loans. They set the pattern. Banks copied them, then innovated new kinds of securitization.
Fannie Mae and Freddie Mac should have been reviewed and revised in 2003. Failing that, in 2005/6. Too many people were too deeply connected with them at the time, and by the time the benefits of revising their role was evident it was too late.