What was the purpose of the Vietnam War?
The Eisenhower administration provided South Vietnam with money and advisors to help stop the threat of a North Vietnamese takeover of the South. The United States also was pledged by treaty (SEATO) to aid the member nations in southeast Asia, if they were attacked by a foreign (communist) power. Following the Eisenhower and Kennedy administrations, President Lyndon B. Johnson also believed in containment and the domino theory. If one nation falls to communism, the next nation will fall, and the next, etc. It became the aim of the Johnson administration to prevent a communist takeover in Southeast Asia. If communism was not stopped in Vietnam, it would spread to other areas of Southeast Asia.
The US couldn't declare a war in Vietnam, that would've implied total war. Total war meant deploying atomic weapons...that would've caused WWIII. The whole purpose of the cold war was to avoid an atomic war...Vietnam was a fuse that could have led to an atomic explosion...a fuse that world leaders wanted to ensure didn't detonate.