Justice Potter Stewart observed in Jacobellis v. Ohio (1964) that while hard-core pornography is difficult to define, “I know it when I see it.” The same is true of evil.

A decent conscience, uncontaminated by ideology, knows what it is looking at. The torments that Hamas “militants” inflicted on Oct. 7—mass slaughter, rape, the beheading and incineration of babies—amounted to behavior that the high court of any uncorrupted intelligence in the world would describe as evil.