I don't think you can say the administration is at fault here. I'm no Bush fan, but I don't believe in blaming someone unless it's their fault.
New York Times Article
What did Barney Frank say at the time?
Legislative outcome?
In the end the Dems blocked the effort after vigorous spending on lobbying by Fannie Mae.
So, I don't think you can argue that there was sleeping going on near the switch. I think you can fairly say that efforts to fix the problem ahead of time were blocked by a strong political effort put forth by those who were fighting for "affordable housing." Now we see how the housing was so affordable, WE get to pay for it!