http://billburnham.blogs.com/burnhamsbeat/2008/07/fannie-mae...
(This got 71 upvotes when posted to News.YC about a month ago.)
The article clearly explains that the political pressures came from Fannie Mae itself. It wanted to lower its lending standards, but was barred by Congress from doing so, presumably because the US Govt was implicitly guaranteeing Fannie's debt. According to the article, Fannie Mae's lobbyists came up with the "affordable housing" campaign to pressure Congress into letting Fannie lower its lending standards.
Congress didn't "force" Fannie Mae to make bad loans. Fannie Mae "forced" Congress to change the law so that Fannie Mae could make bad loans.
Banks have been sued for failing to make "enough" loans in "predominantly minority" areas. Regulators have told banks "we're not going to approve your application to do {thing 1} unless your percentage of minority loans goes up."
This paper was established to advance free market and free trade principles, and it isn't beholden to any US party (it's a British publication).
http://www.economist.com/opinion/displaystory.cfm?story_id=9...
I nearly fell off my chair on the part where they claimed lenders were forced against their will to make the bad loans for "Affirmative Action" reasons... Wow. Just wow.