ritorial expansion in North America, by peaceful means but also by war in 1812 and the Mexican War of the 1850s. Under the Monroe Doctrine of 1823, the United States warned foreign powers against intervening in the affairs of Latin America. Since 1898, the United States has intervened militarily and diplomatically many times in Central America and the Caribbean region as it has deemed necessary to protect its commercial and strategic interests there. British naval hegemony in the Atlantic Ocean enabled the United States to remain free of major military commitments in Europe until German advances forced it to intervene there in 1917-1918 and again in 1941-1945.
In the Pacific, the United States acquired the Philippines as a colony after the Spanish-American war. It also annexed Guam, the Hawaiian Islands and part of Samoa in the 1890s. While European nations vied for spheres of influence on the Asian continent, the United States pursued an Open Door Policy toward China, which was designed to preserve what was left of Chinese sovereignty and to keep China open for American traders. According to Karnow, "there was little inclination in America for dominating foreign territories."
According to Edmonds, "Vietnam was no more than a blip on the American consciousness prior to the closing days of World War II." The Vietnamese had a long history of resistance to foreign invaders. By a series of steps between 1862 and 1893, the French took control of Vietnam, Cambodia and Laos, which together they called French Indochina. According to Hammer, Vietnamese nationalists "fought for independence from France as their ancestors had fought to oust the Chinese from Vietnam from the first century A.D." Edmonds said "the French version of the 'white man's burden' was largely a smokescreen to cover an especially vicious brand of imperialism. France exploited Vietnam ruthlessly."
After Japan occupied southern Indochina in June 1941, Chace said...