Franklin D. Roosevelt was not a proponent of American colonialism or the notion of the United States controlling other nations. In fact, he was a vocal critic of the actions of European countries in acquiring colonies. Roosevelt did, however, realize that acquiring important islands in the Caribbean and Pacific was vital to allow the United States to grow militarily. The goal of territorial expansion under Roosevelt was to secure naval bases in the waters that surround the United States. Roosevelt realized that air and sea power were the future of warfare and in order to continuously defend the continent, the United States would need to be a leader in these areas. Roosevelt understood the strategic value of acquiring islands that could be used for naval and air bases and as refueling stations. This was of special importance with the emergence of Japan as an economic and imperial power in the Pacific.