It appears to be related to this Novak item, which hit the wires today. Novak reported that Gramm and McCain had patched things up and that Gramm continued to be a trusted adviser. Gramm’s rivals within the McCain campaign raised a fuss, and Gramm, I gather, said that he would leave if people thought he was a liability.

From the standpoint of McCain’s interests, I think Gramm’s departure is an overreaction. But it perfectly serves the interests of Gramm’s rivals within the McCain campaign.