Fidel Castro had been in power for two years and the harsh realities of trying to run a strict socialist political and economic programme so close to the United States had begun to take its toll. This only served to increase Castro’s determination to build an egalitarian utopia. In doing so, he had to rely increasingly upon the help and goodwill of the Soviet Union and other Eastern Bloc countries.

On 2 January the victory anniversary parade included Soviet Bloc rocket launchers, tanks and heavy artillery. In his speech, Castro demanded that the United States clear the nest of spies out of their embassy in Havana and leave only eleven people: the same number as staffed the Cuban Embassy in Washington. In response, the United States broke off diplomatic relations with Cuba the next day.

Castro insisted that his regime was not Communist, but by February 1961 he had started to soften these protestations. He acknowledged that Cuba’s Communist Party was ‘the only Cuban party that has always clearly proclaimed the necessity for radical change of the island’s social structure. It is also true,’ he said,

that at first the Communists distrusted me and us rebels. It was a justified distrust, an absolutely correct position, ideologically and politically. The Communists were right to be distrustful because we of the Sierra, leaders of the guerrillas, were still full of petty-bourgeois prejudices and defects, despite Marxist reading. The ideas were not clear to us, though we wanted with all our strength to destroy tyranny and privileges. Then we came together, we understood each other, and began to collaborate. The Communists have given much blood, much heroism, to the Cuban cause. Now we continue to work together; loyally and fraternally.

Sporadic acts of sabotage and terrorism against Cuba ran in parallel with the arrest of spies, such as the CIA’s Carlos Antonio Cabo, and leaders of anti-revolutionary groups still based in Cuba, some of whom were executed. The actions against Castro’s regime culminated in the bombing of Cuban airfields on 15 April and the Bay of Pigs invasion on 17 April.

Two weeks later, chastened to some extent by the attempt to invade but emboldened by its failure, Castro gave a powerful May Day speech at the end of a long day of celebrations. He spoke about the success over imperialism and condemned President Kennedy’s support for the invasion, saying:

He likened Kennedy to Hitler and Mussolini, and continued:

The revolutionary government continued to prosecute and severely punish those who participated in the Bay of Pigs invasion and other acts against Cuba. On 23 September, an American and five Cubans were executed by firing squad for their part in the Bay of Pigs.

Administratively, or perhaps simply organisationally, the economic and social reforms were successful, but they did not bring with them any degree of prosperity. More help was needed. Castro at last succumbed to the inevitable and, on 2 December 1961, declared himself a convert to the Marxist–Leninist cause.