Vietnam had been known as French Indo-China for a hundred years.  Wile the Indo-Chinese had sought freedom, they had continued to be dominated by French Forces.  In 1940 the countrywas overrun by the Japanese who then occupied it.  The first American involvement came in 1945 when a United States military officer was sent as a representative of the Allies, fighting in WWII, to establish contract with Indo-Chinese leaders to harass the Japanese and find escape routes for Allied pilots who had been shot down in the area.  Th eFrench continued control over Indo-China at the end of WWII.  However, a communist Vietnamese resurgent group, the Viet Minh led by Ho Chi Minh, staged an uprising and declared independence in 1945.  War broke out between Ho Chi Minh's  government and the French.  The fighting lasted until 1954 when the Geneva agreement that was reached.

The Diem government that was in place was challenged by Ho's guerilla group, The Viet Cong, in 1957.  North Vietnam gained support of communist China and the Soviet Union.  The South Vietnamese government was aided by the United States.  The administration of president Dwight D. Eisenhower sent money, arms, and military advisors to aid the South Vietnamese.  This aid was part of Eisenhower's program to contain the spread of communism in the world.  Eisenhower feared that if South Vietnam fell to communism soon the rest of Southeast Asia would follow; in other words, there would be a domino effect.

In 1961, the U.S. government, under president John F. Kennedy, continued the aid that Eisenhower had begun.  More military advisors were sent.  In 1962, the first group of special forces, commonly called the Green Berets, were sent.  In 1963, President Diem was assassinated.  Fighting continued but the government was in turmoil.