What was the primary objective of the United States in the Vietnam War?

The primary objective of the United States in the Vietnam War was to prevent the spread of communism. During the Cold War era, the U.S. adopted a containment policy aimed at stopping the influence and expansion of communism globally. The belief was that if one country fell to communism, neighboring countries would likely follow—a concept known as the "domino theory." Therefore, the U.S. intervened in Vietnam to support the South Vietnamese government against the communist North Vietnamese forces and the Viet Cong, aiming to halt the potential spread of communism throughout Southeast Asia. This led to significant military engagement and the commitment of resources by the U.S. to achieve this goal.