Cuban Missile Crisis that the US Navy may not have known about. Khrushchev knew he was losing control. President Kennedy had been told in early 1961 that a nuclear war would likely kill a third of humanity, with most or all of those deaths concentrated in the US, the USSR, Europe and China; Khrushchev may well have received similar reports from his military. With this background, when Khrushchev heard Kennedy's threats relayed by Robert Kennedy to Soviet Ambassador Dobrynin, he immediately drafted his acceptance of Kennedy's latest terms from his dacha without involving the Politburo, as he had previously, and had them immediately
Cuban Missile Crisis U-2 by a Soviet missile violated direct orders from Moscow, and Cuban antiaircraft fire against other US reconnaissance aircraft also violated direct orders from Khrushchev to Castro. Second, the Soviets already had 162 nuclear warheads on Cuba that the US did not then believe were there. Third, the Soviets and Cubans on the island would almost certainly have responded to an invasion by using those nuclear weapons, even though Castro believed that every human in Cuba would likely die as a result. Khrushchev also knew but may not have considered the fact that he had submarines armed with nuclear weapons