It has been over a hundred years since the U.S. took control of Puerto Rico. In that time, the way in which the U.S. perceived Puerto Rico has changed from a colony requiring Americanisation to, in the 1950s, its showcase of democracy in the Caribbean, to today, an island that still retains geopolitical importance for the U.S., but represents an increasing economic burden. The failure of Operation Bootstrap, as the Puerto Rican industrialization program was known, resulted in permanent large-scale unemployment, with a population dependent on federal transfers for a living, and a constant source of migration to the mainland, where over half of Puerto Ricans now live. I shall trace the outline of these three stages in U.S. hegemony over Puerto Rico, and argue that throughout the U.S. Congress was reluctant to fully incorporate Puerto Rico, because its population was deemed racially and socially inferior to that of the mainland. Though the removal of Spain from Puerto Rico, Cuba and the Philippines was considered part of the its ‘manifest destiny’, the United States never intended to incorporate these people so different from the U.S. as part of the American nation, as was done with its earlier acquisitions in Texas, Alaska or even Hawaii.