… is from page 246 of the late James Q. Wilson’s 1993 book, The Moral Sense :
I am struck in reading accounts of some of the most dedicated ideologues by how little the content of the ideology mattered and how much anger at “society,” “the ruling class,” “the government,” “meddling bureaucrats,” or “inferior races” mattered. Anger is the necessary handmaiden of sympathy and fairness, and we are wrong to try to make everyone sweet and reasonable. But anger, like those moral senses that it exists to defend, must be checked by other senses. Those others are self-control and duty. By the same token, self-satisfaction and narrow loyalties, which are emotions growing out of self-control and duty, must be checked by other sentiments, and these are sympathy and fairness.