In the financial crisis, the signature of the credit rating companies has been that they are a day late and a dollar short. In this case, two trillion dollars. S&P made a two-trillion dollar error in the computations that were the basis of its rationalefor downgrading Treasury securities.
But that was petty cash compared to what credit rating companies cost the world economy when they corruptly took money from issuers of sub-prime bonds to help them come up with a formula to justify a triple-A rating.
The entire financial collapse is on the conscience of the credit-raters. If they had the most elementary competence, they would have known that a bond backed by junk had to be junk itself.
So where do these guys get off downgrading the debt of the United States? And why do it after a deal was struck to avoid default rather than before?