Great Britain controlled Singapore and Burma to protect its Indian possessions and gain access to China. France took control of Vietnam, Cambodia, Laos and Annam, combining them into French Indochina to maintain its trade influence. The United States inherited the Philippines from Spain after the Spanish-American War and sought to "civilize" the country while also using it for trade with China. Local rulers maintained indirect rule through cooperation with colonial powers, while direct rule replaced local elites with colonial officials when opposition was strong. Colonial economies developed plantation agriculture and infrastructure through native labor to export goods and profits. Thailand remained the sole independent Southeast Asian state through Western education and diplomacy.