Don Rumsfeld serves at the pleasure of the President of The United States.
I believe the President is pleased to have Mr. Rumsfeld serving as Defense Secretary.
If that displeases a bunch of wimp @ss democraps, then so much the better!
But it's always helpful to remind the President how pleased he is with Rumsfeld, especially when Karl Rove might be whispering something more "nuanced" into his other ear.