The world’s great powers are learning they have limits

History is a guide to the perils of great-power hubris. Back in 416 B.C., the refusal to submit to Athens, the superpower of antiquity, ended badly for the islanders of Melos. All their men, as Thucydides has noted, were massacred, and the children and women enslaved. Yet, at the end of the day, such imperial highhandedness backfired on Athens: It lost the broader war for domination of Greece.