In 1898 the USA declared war on Spain, routed its military and gained control of Cuba, with Puerto Rico, Guam and the Philippines thrown in for good measure. They would all come in useful, but Guam in particular is a vital strategic asset and Cuba a strategic threat if controlled by a major power. In 1898 that threat was removed by war with Spain. In 1962 it was removed by the threat of war with the Soviet Union after they blinked first. Today no great power sponsors Cuba and it appears destined to come under the cultural, and probably political, influence of the USA again.
