Essentially a certain percentage of loans were mandated to be 'handed out' to those unworthy at the behest of liberal lawmakers. Banks just don't decide to make bad loans; they were essentially instructed to and the trail leads all the way back to Clinton's pressuring the parties involved. Had that not happened, then perhaps we would be closer to 99% of the mortgages being considered performing, instead of 95%.
It was the current administration's former treasury secretary, and the fed chairman, and the current republican presidential candidate who all brought the matter to the attention of lawmakers a couple of years ago in public forums. The warnings went unheeded and in fact, McCain sponsored legislation to fix the problem but that was blocked by democrats (oh, the same ones still in majority positions today who are supposed to fix the problem -- laughable; no actually damn scary).
To boot, the top 5 recipients of campaign donations from the GSE's are essentially the same democrats, with the annointed one being at # 3 with over $105,000. What was the quid pro quo. Talk about criminal!
The only hope is that the assets to be purchased at a vast discount are someday sold above 'par', and the taxpayers are made whole. I'm not holding my breath though, because I still see who maintains the majority in Washington, and the purse strings.