As the Cold War became warmer, the U.S.(United States) and the U.S.S.R.(United Soviet Socialist Republics) became ever so tense with each other regarding their nuclear situation. Each had been campaigning to bring down the other through small conflicts but came to no avail. After former leader of the U.S.S.R. Joseph Stalin died, relations with the United States became even harder with Russian and American politicians campaigning to stop the other's ideology. 

When Kennedy came into office in 1959, he was brought into the very anti-communist United States and struggled to find good relations with the Soviet Union. Khrushchev was brought into office in 1953 after Stalin died and was brought into a starving, highly corrupt U.S.S.R. , longing for some political victory against N.A.T.O. (North Atlantic Treaty Organization) 

Khrushchev, with much on his hands regarding the supply crisis in the Soviet Union and himself trying to keep the stability of his party, decided to make a large move against the United States regarding stationing missiles on the island of Cuba thanks to his new ally, Fidel Castro. He and Castro would spend time together carefully preparing a plan to get the missiles into Cuba without the United States knowing. 

Back in the U.S. however, there was a different situation regarding John F. Kennedy and Fidel Castro. After a failed invasion to try stopping the communist regime in Cuba called the "Bay of Pigs", Kennedy sought his advisors for advice. Walter Poole, head of the Joint Cheifs of Staff at the time said that "The Joint Cheifs of Staff saw Fidel Castro's regime as a cancer that must be removed, by whatever means proved necessary."(TIME: Inside JFK's decisionmaking during the Cuban Missile Crisis) This shows that Kennedy's administration was proactive in their effort to stop the spread of communism from going any further in order to weaken the allies of the U.S.S.R. ​​​​​​​