The United States was a latecomer to the Pacific. By the time the revolution was over most of the islands had been discovered and claimed many times. American seamen and guano workers did discover some minor islands and lay the basis for claims to others that became important with the advent of transoceanic planes. As was true of other nations, American naval officers and citizens claimed islands and worked to have them annexed to the United States but received little backing from the home government. During the War of 1812 Captain David Porter, U.S.N., raised the American flag over Nukahiva, one of the Marquesas. There is some question whether the natives understood the treaty that they signed. Porter's annexation was not followed up.
Early American interest in the Pacific centered around the whaling industry. Between 1839 and 1842 an American squadron, under command of Lieutenant Charles Wilkes, U.S.N., carried out an extensive scientific expedition in the Pacific. The main objective of this expedition was to aid the whaling industry. The Perry expedition ( 1852-1854) resulted in the opening of Japan to outside contacts. Perry strongly recommended that the United States acquire naval bases in the western Pacific, but again nothing was done.During the 1870's there was increasing American interest in the Samoan Islands. Through the efforts of local American citizens, a treaty of annexation was drawn up but not ratified by the United States. In 1877 the United States did accept Pago Pago as a naval base. In 1899 the United States annexed eastern Samoa in order to keep the Germans out.Because of the activities of the missionaries, the United States long held a dominant position in the Hawaiian Islands. In 1893 a group of Americans overthrew the native monarchy with an idea of annexation by the United States. President Cleveland did not approve of the methods employed, and annexation was delayed until the strategic importance of these islands was demonstrated in the Spanish American War. They were finally annexed in 1897. As a result of the Spanish American War, Spain ceded the Philippine Islands and Guam for $20,000,000. The Philippines were granted their independence on July 4, 1946. The United States occupied the Japanese mandated islands during the Second World War and afterwards received them as a trust territory from the United Nations.