Ngo Dinh Diem was selected to lead the government in South Vietnam by the U.S in 1955. Diem regime was strongly anti-communism and French connection. He was one of the few prominent Vietnamese nationalist who could claim both attributes.
During the time as the US president, John F. Kennedy increased American economic and military aid in three times to support the South Vietnam government and sent more U.S military advisors in Indochina. He rejected the withdrawal from Vietnam War.