If Khrushchev had not, surprisingly, initiated an abrupt, humiliating withdrawal of his missiles Sunday morning—without even waiting for an official American response to his proposal of Saturday morning, which Kennedy had argued to his advisors was “very reasonable”—there was every likelihood of the fuse to all-out war being lit by that afternoon.
How close did that come? As close as the unpredictable decision of one man to overrule two others on a Soviet submarine [preventing the use of a nuclear torpedo of which the Americans knew nothing], or the inaccuracy of Cuban antiaircraft gunners (improving every hour) on their first day of firing at live targets. Far greater than one in a hundred, greater that day than Nitze’s one in ten. And that was for reasons which I didn’t know, and no other Americans knew, for thirty and in some cases forty years. The world has yet to absorb the lessons of this history—the story of how the existence of humanity was placed in great, unjustifiable danger by men who had no intention of doing that, men who recoiled from ending human history, or from taking what they saw as a high or even significant risk of doing so.
A primary lesson I draw from this episode is that the existential danger to humanity of nuclear weapons does not rest solely or even mainly on the possibility of further proliferation of such weapons to “rogue” or “unstable” nations, who would handle and threaten them less “responsibly” than the permanent members of the Security Council, nor does it rest merely on the vagaries of the smaller and more recent nuclear weapon states of Israel, India, Pakistan, and North Korea (though these do enhance the dangers).
What a true history of the Cuban missile crisis reveals is that the existence of masses of nuclear weapons in the hands of leaders of the superpowers, the United States and Russia—even when those leaders are about as responsible, humane, and cautious as any we have seen—posed then, and still do, intolerable dangers to the survival of civilization.
Ellsberg, Daniel. The Doomsday Machine: Confessions of a Nuclear War Planner. Bloomsbury, 2017. p. 220–1