On Feb. 14, 1989, I happened to be on a panel on press freedom for the Columbia Journalism Review when someone in the audience told us of Ayatollah Ruhollah Khomeini’s religious edict for blasphemy against the British novelist Salman Rushdie. What did we think? We didn’t, as I best recall, disgrace ourselves. We said most of the right things about defending freedom of thought and the imagination.

But the death sentence from Iran’s supreme leader seemed unreal—the sending of a thunderbolt from medieval Qom against modern Bloomsbury—and...