To understand the furor over the decision by Standard & Poor’s, the rating agency, to downgrade U.S. government debt, you have to hold in your mind two seemingly (but not actually) contradictory ideas. The first is that America is indeed no longer the stable, reliable country it once was. The second is that S.& P. itself has even lower credibility; it’s the last place anyone should turn for judgments about our nation’s prospects.

Let’s start with S.& P.’s lack of credibility. If there’s a single word that best describes the rating agency’s decision to downgrade America, it’s chutzpah.

Standard & Poor’s, the rating company that downgraded the debt of the United States to AA+ from AAA for the first time, now finds itself assailed by investors led by billionaire Warren Buffett for making a political decision that has more to do with Tea Party politics than the financial stability of the U.S