The involvement of the US in Vietnam was largely a result of the containment policy, which was aimed at stopping the spread of communism. The US saw Vietnam as a crucial front in the Cold War struggle against the Soviet Union and China, both of which supported the communist North Vietnamese forces. The US believed that if South Vietnam fell to communism, other countries in Southeast Asia would follow suit, leading to a domino effect that could threaten US interests and security. As a result, the US committed significant military and economic resources to support South Vietnam and prevent the spread of communism in the region.
