Examples of clearcut ad hominems, I’ve found, are rarer than I thought before I started looking for them. On closer inspection, most ad hominem arguments have a trace of logic or reason, however weak, that accompany them. But William Greider’s argument against Standard & Poor’s warning on U.S. government debt is about the cleanest case of an ad hominem I’ve come across in a while.

I have nothing personal against Greider. I sat around a conference table with him for a day in February 2010, a day biiled as one on which left (he’s on the left) and right (I’m not on the right, but I’m not on the left either) tried to see if we could work together against the various wars. He seems like a nice man.

In a recent article in which he railed against Standard & Poor’s for its recent lowering of U.S. government bonds from “stable” to “negative,” Greider uses the whole column to attack Standard & Poor’s. Much of his attack is on target. Standard & Poor’s did do us a disservice by rating securitized mortgages too high. But Greider doesn’t give us a scintilla of evidence that their fear on U.S. government debt is unjustified. Indeed, the standard problem with Standard & Poor’s is that they have rated various securities too high. So, given their bias in the direction of ratings that are too high, isn’t it striking that they have moved slightly in the opposite direction? Not to Greider.

He also states, “What is required is a serious law that either changes the status of the rating agencies or shuts them down.” Is Greider aware that the SEC gave privileged status to Standard & Poor’s in 1975, a status that takes away much of their incentive to rate accurately?