A moral puzzle

Trump has all his life posed a moral puzzle: What is due in the way of kindness and sympathy to people who have no kindness and sympathy for anyone else? Should we repay horrifying cruelty in equal measure? Then we reduce ourselves to their level. But if we return indecency with the decency due any other person in need, don’t we encourage appalling behavior? Don’t we prove to them that they belong to some unique bracket of humanity, entitled to kick others when they are writhing on the floor, and then to claim mercy when their own crimes and cruelties cast them upon the floor themselves?

David Frum, What Did You Expect of Donald Trump? - The Atlantic