The US had lost the Vietnam War and also taken a major blow in the Cold War. missing-in-action are listed on the wall. The Vietnam War can be considered a "proxy" war in the Cold War. Although the Soviet Union and the United States did not directly go to war, they each supported a different side in the war.
Furthermore, why was the United States involved in the Vietnam War?
The U.S. government viewed its involvement in the war as a way to prevent a communist takeover of South Vietnam. This was part of the domino theory of a wider containment policy, with the stated aim of stopping the spread of communism.
Why did the United States become involved in the Vietnam War?
The US got involved in the Vietnam War because it did not want another country going to communism (and therefore the Soviet sphere of influence) after what happened in China. Vietnam, Laos and Cambodia had been combined into a French colony called "French Indochina" back in 1887.