Here's one possible suspect in the mystery of which Republican senator put a hold on the nomination of federal prosecutor Neil Barofsky for the key post of special inspector general for the bailout.

During Barofsky's appearance before the Senate banking committee November 19, Kentucky GOP senator Jim Bunning -- who from the beginning has been a staunch opponent of the bailout as a whole -- made clear that he opposed the nomination. Bunning expressed concern about the Treasury's decision last month to change its plan for how to use the bailout money, and about Barofsky's apparent reluctance, at a previous hearing, to question that decision by Treasury.

From the hearing:

Bunning: The bailout law also allows $50 million for your office, and so you will have a very ample amount of resources.

But I have serious concerns with your nomination. The nominee may be a dedicated public servant. He appears to be a skilled prosecutor and a man of integrity. But I wonder why taxpayers should have to pay $50 million to a watchdog who will have nothing to watch. How willing (sic) the IG performs (sic) his statutory role when the secretary has rewritten the law already, less than two months after it was enacted.

...

In his testimony earlier this week, Mr. Barofsky did not question Secretary Paulson's unlikely interpretation of the bailout law. Now, that's the money that is spent; if he does not question it, he will have little to do but watch the preferred stock positions mature.

...

Ultimately, I believe Mr. Barofsky, with his impressive legal skills, can serve the public far better in the Southern District of New York, where he can continue to prosecute mortgage fraud.

To be clear: Bunning, or any other senator, has a perfect right to oppose Barofsky's nomination for the reasons he suggests above. But anonymously preventing a free vote on the issue, especially at a time of such urgency, hardly offers a model of the kind of openness and transparency that Congress is calling for from the Treasury Department.

We've put in a call to Bunning's office, and will let you know what we hear.