Rummy's Lifebuoy?
"Let's say Rumsfeld resigns on Friday. The election is still six months away. And the nation is at war. So a new Defense Secretary would be needed more or less immediately. That would open up a very uncomfortable prospect for the administration.

Confirmation hearings for a new Sec Def would, I think, inevitably turn into a national forum for discussing the management of the Pentagon, the planning for the war and the lack of planning for the occupation. The new nominee would be drawn into all sorts of uncomfortble public second-guessing of what's happened up until this point. Sure, that's stuff under Rumsfeld. But, really, it's stuff under Bush -- the civilian head of the United States military.

That, I have to imagine, is something the White House would like to avoid at any cost."