The problem, as Think Progress points out, is that Special Prosecutor Patrick Fitzgerald is a Republican poster child. Cue Arnold taking bows for foreseeing the slime-and-defend attack on Fitzgerald and the appropriate response more than a year ago. Not that it was terribly difficult to foresee the attack given this administration's previous tactics--including, of course, the original outing of Plame as a means of discrediting the (true) account published by her husband of his trip to Niger.
By the way, you've gotta love the sight of the usual GOP suspects decrying the "partisan" nature of Fitzgerald's investigation. Where were these people when Ken Starr was put in charge of investigating Whitewater? Now there was a special prosecutor (or independent counsel, as the term then was under the since-expired statute) who abhorred the administration he was investigating. And the same, in spades, goes for the (false) accusation that Fitzgerald has exceeded his mandate by investigating violations of anything other than one particular statute--again, does anyone remember the roving Starr investigation?
Frankly, I wouldn't like to see the Democratic version of Starr investigating this administration, much as I suspect they've done plenty of bad things. What happened then wasn't good for democracy or for our political process. But, at least so far, there's no evidence that Fitzgerald has done anything even close to what Starr did, and I haven't seen any indication that his investigation has been inappropriate or improper in any fashion.
Doesn't mean that I'll agree with any indictments that might be handed down, and sure doesn't mean that anyone he accuses should be deprived of the presumption of innocence, but he's hardly Javert or (as John Tierney accused him of being) Captain Ahab.