<span>The domino theory, which governed much of U.S. foreign policy beginning in the early 1950s, held that a communist victory in one nation would quickly lead to a chain reaction of communist takeovers in neighboring states. In Southeast Asia, the United States government used the domino theory to justify its support of a non-communist regime in South Vietnam against the communist government of North Vietnam, and ultimately its increasing involvement in the long-running Vietnam War (1954-75). In fact, the American failure to prevent a communist victory in Vietnam had much less of a global impact than had been assumed by the domino theory. Though communist regimes did arise in Laos and Cambodia after 1975, communism failed to spread throughout the rest of Southeast Asia.
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Answer: In a general sense, World War I and World War II were wars conducted on a massive scale unlike any other wars in history. They were similarly caused by nationalism, imperialism, alliances, and militarism. Both wars saw countries trying to upset the power balance in Europe for their own gain.
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<span>The Native Americans quickly began to die in huge numbers from diseases imported by the Europeans.
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B 19th country Italy before unification