Instead of the air strike, JFK initially chose to impose a naval blockade on further arms shipments to Cuba. Yet as the Soviets rushed to complete construction of missiles already in Cuba so that they could be fired against American cities, US planning for the air strike was refined.
As Soviet ships approached the blockade line on Oct. 24, 1962, Robert Kennedy wrote that “the danger and concern that we all felt hung like a cloud over us all…I think these few minutes were the time of greatest worry by the President. His hands went up to his face and covered his mouth and he closed his fist…I felt on the edge of a precipice and it was as if there was no way off.”
While the Soviet ships turned around rather than challenge the blockade, the window for US action to prevent the missiles in Cuba from becoming fully operational was rapidly closing. At the State Department on Oct. 26, RFK scribbled down Secretary of Defense Robert McNamara's insistence that after an airstrike against the missile sites, an “invasion must follow!!” The plan called for 500 bombing sorties against Cuba followed by an invasion force of 90,000 American soldiers.
As both sides moved military pieces on the chessboard toward the precipice of nuclear war, both President Kennedy and Soviet Premier Nikita Khrushchev also intensified the search for an alternative. In a private letter from Khrushchev to JFK that arrived on Oct. 26, Khrushchev admonished Kennedy not to “pull on the end of the rope in which you have tied the knot of war, because the more the two of us pull, the tighter that knot will be tied.” RFK’s notes highlighted that phrase.