I used to nod wisely when people said: "Let's discuss issues rather than personalities." It seemed so obvious that in politics an issue was an issue and a personality was a personality, and that the more one could separate the two, the more serious one was. After all, in a debate on serious issues, any mention of the opponent's personality would be ad hominem at best and at worst would stoop as low as ad feminam.
At my old English boarding school, we had a sporting saying that one should "tackle the ball and not the man." I carried on echoing this sort of unexamined nonsense for quite some time--in fact, until the New Hampshire primary of 1992, when it hit me very forcibly that the "personality" of one of the candidates was itself an "issue." In later years, I had little cause to revise my view that Bill Clinton's abysmal character was such as to be a "game changer" in itself, at least as important as his claim to be a "new Democrat." To summarize what little I learned from all this: A candidate may well change his or her position on, say, universal health care or Bosnia. But he or she cannot change the fact--if it happens to be a fact--that he or she is a pathological liar, or a dimwit, or a proud ignoramus. And even in the short run, this must and will tell.