The claim that Kennedy's offer to withdraw Jupiters from Turkey is what saved the day makes a nice story, but, unfortunately, an historically false one. Before the message Robert Kennedy's delivered to the Russian ambassador in DC could reach Moscow, Khushchev had already agreed to withdraw the Cuban deployments.

Kennedy, to this credit, did not renege on his offer. What is even less widely known, Khushchev also withdrew tactical nuclear weapons from Cuba which Kennedy at al were totally unaware of at the time. (In part, because he had be aghast at Castro suicidal tendencies during the crisis.)

If the hotheads in the Pentagon had had there way and had gone ahead with an invasion of Cuba, those tactical weapons, which had been pre-authorized for use in such lose-it-or-lose-it circumstances, would have been truly devastating -- and not only to the invading forces.