Excerpt from Cambodia: Year Zero
Published in Cambodia: Year Zero, 1978

From the mid-1960s to 1973, the United States and its allies in South Vietnam fought a long war against Soviet-supported Communist forces concentrated in North Vietnam. (Communism is a system of government in which the state plans and controls the economy and a single, often authoritarian state.) This war eventually expanded throughout much of Southeast Asia, involving the neighboring nations of Laos and Cambodia. The opposition of American citizens to the war forced the government to withdraw its troops, and in January 1973 the United States signed a peace treaty with North Vietnam.

Meanwhile,...