Thanks to
Naked Capitalism, got this link to a story entitled:
An Autopsy of Fannie Mae and Freddie Mac,
here...Most uninformed folks, usually in the opposition seats, like to use Fannie and Freddie's faults to obscure the damage done by deregulation and fraud mar.., er, I mean free markets, by yipping like an annoying chihuahua about F&F. This story is the clearest quick explanation yet of their involvement, and it links to an in-depth report by their "overseer at the Federal Housing Finance Agency". Their behavior was wrong, but had nowhere near the impact of those who were motivated more by the appetite for high-interest securitized loans rather than the ability for borrowers to pay back money. Most of the troublesome loans were not written or bought by them because such paper was well out of their guidelines. And even today, when compared to the loans private capital pushed on people, their default rate is not even close.
Barry Ritholz in "Bailout Nations" analogy points out that that their effect was more like throwing stones at a body on it's way down after falling off a tall building. The bubble was bursting as early as 2005 and 2006, and these links make it clear that their major participation didn't even come until the crooks had left the building (to look for taxpayer bailout money, as it turns out).