… is from page 13 of my colleague Dan Klein’s November 2020 working paper titled “Adam Smith and Propriety in Moral and Political Discourse ” (original emphasis):
I am not one to say that ad hominem arguments play no role in navigating discourse. In a court case, motive and character do play a role. But that role is limited; it may give grounds for suspicion and further investigation. The real work is in arguing the evidence. In political discourse, the real work is in arguing for one’s position as compared to the other person’s position. In such argumentative engagement, it is irrelevant what a person’s motives, personal habits, associations, and income sources are. To harp on such ad hominem irrelevancies is to confess the weakness of one’s argument.