The administration knew about the warning from s&p from what I heard long before the downgrade happened. The tea party and many republicans have been working since Jan to get budgets and deficits in line. And fighting this administration on their policies I might add.
Could it be possible this downgrade was allowed to happen to take out the tea party and some republicans? Get them out of the way of their agenda.
This article spells it all out what they are after.

http://www.foxnews.com/politics/2011/08/07/blame-game-vitriol-demonstrates-sp-disgust/