Kennedy stated in his inaugural address that the United States was prepared to "pay any price, bear any burden, meet any hardship, support any friend" to guarantee "liberty" around the globe. This was his way of affirming the US would continue as the active leader of the anti-communist free world. It was also a strong assertion that Kennedy would aggressively maintain the long-standing US policy of containing communism's spread.

The years of the Kennedy administration were tense. But Kennedy, a product of World War II, was determined that the United States would not practice the kind of appeasement toward the USSR that France and Great Britain had shown towards Hitler. He knew that the Soviets respected strength. He was determined to show it so that the rival nation would understand that it would pay a price if it tried to expand its influence.

For example, when Khrushchev threatened to take over West Berlin, Kennedy met the challenge by stationing more troops and weapons in the area. In response, the Soviets backed down and instead built a wall separating the two sides of Berlin. In Vietnam, Kennedy was also ready to contain the threatened spread of communism by deploying the military, though initially at a limited capacity.

Perhaps the biggest affront to longstanding U.S. foreign policy doctrine was Khruschev's attempt to install nuclear weapons in Cuba. Since the days of Theodore Roosevelt, the US had aggressively defended the entire Western hemisphere and was willing to risk nuclear war to keep Soviet weapons out. Crucially, Kennedy was able to diplomatically maneuver the Soviets into standing down.

Kennedy made some mistakes in containing communism, such as U.S. involvement in Vietnam. At the same time, he managed to successfully communicate to the Soviets that he and the US would act swiftly and decisively to protect its spheres of influence.

Kennedy did not want to be seen as soft on communism. He and his staffers took great pains to keep a strong footing in the face of rising tensions between the Soviet Union and the United States. Kennedy did not want to fall into the same trap as the last Democratic president, Truman, whose administration was marked by Soviet gains and a permanent stalemate in Korea.

During the 1960 election, Kennedy claimed that the Soviet Union had more missiles than the United States and that he had a plan to close this "missile gap." Even though the gap did not exist, this was part of the strategy that helped defeat Richard Nixon.

Kennedy authorized the Bay of Pigs attack even though he had misgivings towards the plan's success. Kennedy did not want the Cuban rebels to be told that the president killed their idea, as it would appear as though he was weak in the face of potential Soviet aggression. Kennedy also blockaded Cuba during the Cuban Missile Crisis, though he opened back channel communication with Nikita Khrushchev. The secret communications allowed the Soviet commander to back down while still appearing strong to the Politburo and his communist allies.

Kennedy increased the amount of aid to South Vietnam and sent military advisers to fight against communism. He also started the Alliance for Progress in order to combat communism in Central America. Kennedy increased STEM research in order to create more scientists that could be used for national defense. Kennedy's defense policy was to use a "flexible response," which increased American non-nuclear military capacity. This gave the United States the ability to intervene in the developing world without risking a nuclear attack that would destroy mankind. Though his administration was cut tragically short, the American people could say that Kennedy was tough on communism.

John F. Kennedy, who served as the 35th president of the United States (1961–63), believed strength and toughness were needed to win the Cold War. Although his presidency was brief, JFK faced numerous foreign policy challenges.

The first foreign crisis he faced was the Bay of Pigs fiasco in April 1961. The CIA trained Cuban exiles and landed them in Cuba to overthrow Fidel Castro. It was an embarrassing failure for the United States. Although Kennedy had not planned the invasion, he did approve it.

Kennedy's determination to fight Communism was evident. In 1963, he gave his "Ich bin ein Berliner" speech in West Berlin. In this famous speech, he pledged his support for the beleaguered people of West Berlin. He also sent advisers to Vietnam and deepened America's involvement in that nation.

Kennedy also created the Peace Corps to assist poorer nations throughout the world. It remains as one of his most important legacies.

The most dangerous event of his presidency was the Cuban Missile Crisis (1962–63). Satellite photos revealed that the Soviet Union had placed missiles in Cuba. Kennedy demanded that Moscow remove the missiles, and the world came closer than ever to a nuclear war. Moscow finally agreed, and war was averted.