Actually, no, your argument is invalid, because 1) The United States used nuclear weapons in Japan because an invasion of the Japanese Mainland would have likely been too costful on human life, 2) The Americans had nuclear weapons WELL BEFORE Vietnam, and 3) Sure it isn't because the numerous other reasons that the Americans and South Vietnamese lost, i.e. President Eisenhower firing some of his best generals, such as James Doolittle; the North Vietnamese receiving air support from the Chinese and Soviets; the North Vietnamese utilizing Guerilla Warfare, unlike the Americans; et cetera?

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