clinton rossiter, richard neustadt and also james david barber. and you used the, positive/negative, that whole james david barber way that he looks at presidents. can you explain that and why you used that? and then you used a method that didn't necessarily track with his. >> guest: barber has... c-span: who is he, by the way? >> guest: james david barber is a very senior professor at duke university who wrote a very influential book called "presidential character," and he employs a methodology typically called psychobiography, in which he examines the biographies of individuals, in this case, presidents, and tries to arrive at a judgment about their future behavior based upon elements of their past. and he breaks it down into four categories: whether they're active or negative, and whether they're passive or--excuse me--passive or active and--and positive or negative. and so active/positive usually are democrats, and for mr. barber. and kennedy would be an active/positive. someone who puts tremendous energy into his activities in office, but he's