<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.
I hope this was of help.
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Under the Constitution, the president is the federal official that is primarily responsible for the relations of the United States with foreign nations. The president appoints ambassadors, ministers, and consuls (subject to confirmation by the Senate) and receives foreign ambassadors and other public officials
United States participation in the ICC treaty regime would also be unconstitutional because it would allow the trial of U.S. citizens for crimes committed on U.S. soil, which are otherwise entirely within the judicial power of the United States.