"McCain's political colleagues, however, know another side of the action hero -- a volatile man with a hair-trigger temper, who shouted at Sen. Ted Kennedy on the Senate floor to "shut up," called his fellow Republican senators "shithead," "fucking jerk," "asshole," and joked in 1998 at a Republican fundraiser about the teenage daughter of President Clinton, "Do you know why Chelsea Clinton is so ugly? Because Janet Reno is her father." As recently as a few months ago, McCain suddenly rushed up to a friend of mine, a prominent Washington attorney, at a social event, and threatened to beat him up because he represented a client McCain happened to dislike, and then, just as suddenly, profusely and tearfully apologized."
http://www.salon.com/opinion/blumenthal/2007/01/18/mccain/index.html?source=search&aim=/opinion/blumenthal