From the outset of his presidency, Kennedy yearned for Castro to be removed from power. JFK subscribed to the Domino Theory, which argued that if a country fell to communism, its neighbors would follow. And, Castro capitulated to the whims of his communist ally, Nikita Khrushchev, Premier of Russia.
Dwight Eisenhower was the 34th president of the United States. He popularized the theory that if one country fell to communism the surrounding nations were likely to do fall to it as well. It created a domino effect, which is why it was known as the 'Domino Theory'