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. President Lyndon B. Johnson also believed in containment and the domino theory. If one nation falls to communism, the next nation will fall, etc. It became the aim of the Johnson administration to prevent a communist takeover in Southeast Asia. If communism wasn't stopped in Vietnam, it would spread to other areas of SE Asia.