You don't have to fire a nuclear weapon to gain a strategic advantage from it. This is perhaps the most important lesson from the decades of the Cold War. Yet many commentators on the possibility of a nuclear Iran overlook this truth and argue that we could handle this radically new situation.

A nuclear Iran is usually discussed at a cosmic level of abstraction, in terms of deterrence and containment. But it needs to be examined from the bottom up, in concrete detail. War games, which have a long history in U.S. defense planning,...