Final answer:
Cuba became a communist country after Fidel Castro led the Cuban Revolution and overthrew the Batista regime, later adopting communist policies and aligning with the Soviet Union.
Step-by-step explanation:
Cuba became a communist country after the successful overthrow of Fulgencio Batista's government by Fidel Castro and his followers during the Cuban Revolution. Starting in the Sierra Maestra, Castro rallied the Cuban people and by the end of 1958, had gained power with popular support. Initially, after assuming power, Castro did not declare Cuba communist, but his subsequent actions such as nationalizing foreign companies, including U.S. businesses, instituting land reforms, and seeking assistance from the Soviet Union due to U.S. sanctions, led to the establishment of communism in Cuba.
Despite early assurances that he was not a communist, Castro's policies increasingly reflected communist ideologies. The United States responded with economic sanctions and diplomatic isolation which pushed Cuba closer to the Soviet Union. Castro never held the free elections that he had promised, and instead, he cracked down on dissent and suppressed free speech, solidifying communist rule under his leadership until he turned over power to his brother Raúl Castro in 2006. As the situation in Cuba evolved, the U.S. made several attempts to weaken or remove Castro's government, including the failed Bay of Pigs invasion.