Wasn't Burr also the last vice-president to shoot someone?:

"'President promised two years ago that he would fire the leaker. He hasn't kept his promise. Karl Rove is not only still working in the White House, but he has security clearance. Now it turns out that the vice-president of the United States may have been responsible for those leaks for political reasons. That is the kind of thing that has not been done to my knowledge since Aaron Burr was vice president.' Howard Dean- Face the Nation, February 12th, 2006"