Why hasn’t the world been destroyed in a nuclear war yet?

Even after the sub incident was resolved, the larger missile crisis remained. There were plenty of moments when the standoff might have broken down and belligerent impulses taken hold. Former secretary of state Dean Acheson said it was “plain dumb luck” that got us through the crisis with no nuclear detonations.

But after all these nuclear near-misses, one starts to wonder if it really is plain dumb luck. The Nash equilibrium accurately describes a certain kind of rational, perfectly logical approach to choices under conflict. And exactly in keeping with game theorists’ advice, the USSR and U.S. went to great lengths to make sure their arsenals would be feared as legitimate threats. Yet each time they had an opportunity to make good on those threats—to launch a crushing response to an apparent attack or mercilessly exploit a weakness, as many armchair analysts recommended—something held them back: a disobedient soldier, a circumspect engineer, an optimistic leader. The two nations were engaged in a battle of wills, staring each other in the eyes, and they both blinked. Repeatedly.

Maybe, when millions of lives hang in the balance, people are not so rationally cold-hearted as those old game-theory models imply. Or maybe they’re using a different kind of rationality.