Beyond reproducing Mike's post, I want to underline this graph from David Min:
This punches a hole in the argument that Pinto and Wallison make that Fannie and Freddie were making "dangerous loans" when they moved to higher LTV and lower FICO lending. Their models allowed for offsets--if one had a very low LTV, one could get by with a relatively low FICO, and vice versa. The private label market allowed for lending standards that were crappy in all dimensions.
