Strange, but from a historical point we've also seen both the Bushes on Letterman as well as Delay, Newt, MCCain (RINO) and a string of other Republicans. I'll bet the moonbats were calling him a Republican shill. I guess you can join the moonbat's ranks as a certified member of the Reynolds Wrap Bridgade.
I could not have watched this though - my blood pressure could not have stood it.