The main goal of the Vietnam War was to prevent the spread of communism in Southeast Asia. The United States aimed to support the South Vietnamese government against the communist North, fearing that a victory by North Vietnam would lead to a domino effect, where neighboring countries would also fall under communist influence. The war became a contentious issue in the United States, leading to widespread protests and societal divisions. Ultimately, the war concluded in 1975 with the fall of Saigon and the unification of Vietnam under communist control, thus failing to achieve its objective of containing communism in the region.