History of Vietnam since 1945 unstable as no government could keep power for long. There were more coups, often more than one every year. The Communist-run Viet Cong expanded their operation and scored some significant military victories during this period. In 1965, US President Lyndon Johnson sent troops to South Vietnam to secure the country and started to bomb North Vietnam, assuming that if South Vietnam fell to the Communists, other countries in the Southeast Asia would follow, in accordance with the domino theory. Other US allies, such as Australia, New Zealand, South Korea, Thailand, the Philippines, and Taiwan also sent troops to South Vietnam.
1961 in the Vietnam War implementation of the expanded military aid to South Vietnam. He listed three tenets: (1) We have great authority from the President; (2) Money is no object; and (3) The one restriction is that combat troops will not be introduced. In closing the meeting McNamara said the job of the U.S. military "was to win in South Viet Nam and if we weren't winning to tell him what was needed to win." Cryptologist Corporal James T. Davis became the first American member of the United States Army Security Agency to be killed in Vietnam. He and 8 South Vietnamese soldiers were