" When Castro learned of the deal made without him, he was furious and felt betrayed by what he considered his ally. Castro, acting on his own, demanded that the United States stop the blockade of the island, and end its support for the militant Cuban dissidents in exile. He also insisted that the United States return Guantánamo Naval Base to Cuba and stop violating Cuban airspace, as well as its territorial waters. The United States totally ignored him and his demands, dealing instead directly with the Soviet Union. Castro feeling slighted did the only thing left for him, and refused to allow the United Nations access to inspect the missile sites for compliance with the withdrawal agreement.
Although costly, the Soviet Union thought of this entire “missile exercise” as a display of Communist power in the Americas. This was a total disregard of the Monroe Doctrine regarding foreign influences in the Americas. Although ultimately it was a futile attempt, the Soviet Union hoped that it would inspire other Latin countries to follow the move towards Communism. During the next two decades, many attempts were made by Cuba to influence other Latin American countries to accept Communism. This influence was exercised primarily by inserting sympathetic leftist leaning movements into their political structure. However most of these attempts failed with the exception of Nicaragua. In 1967 “Che” Guevara attempted such a blatant movement in Bolivia. In time however many of these Latin countries such as Venezuela, took a shift to the left through their constitutional electoral process and embraced socialistic forms of government on their own. "

― Hank Bracker