The Cuban revolution under Castro was viewed by the US as defeat of its foreign policy towards the Latin America. The US believed that if Castro were to become powerful in Latin America, he was going to be a threat to its safety. US foreign policy promotes democracy and respect of the rule of law in the world.
Since the president of Cuba did not care much about the relationship he had with America, the US governments increased its economic sanctions towards Cuba and stopped buying sugar from there. This was a big blow to the economy of Cuba since it depended a lot in agriculture and agricultural exports. The US government stopped supplying its former business partner with oil. Castro started importing oil from the soviet but “things got worse in 1990 and 1991 as the Soviets ended shipments of subsidized oil, forced Cuba to sell its sugar at market prices, and removed troops from the island”