There was no specific factor that led the united states into getting involved in the Vietnam war, but rather a gradual series of events and decisions which would lead them down such a path. The initial reasons for U.S. involvement in Vietnam seemed logical and compelling to American leaders. From Washington's perspective, by the end of World War II the principal threat to U.S. security and world peace was Stalin's dictatorship and the influence and spread of communism which was emanating from the Soviet Union. Any communist anywhere, in the United States or anywhere else, was, by definition, an enemy of the United States. Drawing an analogy with the unsuccessful appeasement of fascist dictators before World War II, the Truman administration believed that any sign of communist aggression must be met quickly and forcefully by the United States and its allies. This reactive policy was known as containment.
Ho Chi Minh and the Vietminh front that he had created in 1941, had become the target of containment in Vietnam. Ho was a communist, as were his chief lieutenants and they had long-standing connections to the Soviet Union. They were also passionate Vietnamese nationalists who fought to rid their country, first of the Japanese and then, after World War II ended in 1945, to prevent France from re-gaining its former colonial status over Vietnam and the rest of Indochina. Harry S Truman and other American leaders, having no sympathy for French colonialism, favoured Vietnamese independence. However, in eastern Europe, expanding communist control and the victory of the communists in China's civil war made France's war against Ho Chi Minh seem an effort to stop the spread of communism rather than a colonialist effort. The United States decided to support the French position in Vietnam when France agreed to a partially-independent Vietnam under Emperor Bao Dai as an alternative to Ho Chi Minh. This began a long steady rise in American involvement which would see the united states get more directly involved in the years to come.
The United States saw Vietnam as a Cold War battleground. They largely ignored the struggle for social justice and national sovereignty occurring within Vietnam. American attention focused primarily on Europe at the time. Aid to France in Indochina was offered in return for French cooperation with America's plans for the defence of Europe through the NATO. In 1949 China became a communist state. Japan became a huge importance to Washington, and Japanese development required access to the markets and raw materials of Southeast Asia. The outbreak of war in Korea in 1950 served primarily to confirm Washington's belief that communist aggression posed a great danger to Asia. Truman was accused that he had "lost" China and had settled for a stalemate in Korea. This caused succeeding presidents to fear what the reaction both publicly and politically would be if they had "lost" Vietnam. This apprehension, an overestimation of American power, and an underestimation of Vietnamese communist strength locked all administrations from 1950 through the 1960s into a firm anticommunist stand in Vietnam.
However American policymakers failed to appreciate the amount of effort that would be required to exert influence over Vietnam's political and social structure. This course that the American policymakers took led to a steady escalation of U.S. involvement. President Dwight D. Eisenhower increased the level of aide to the French but continued to avoid military intervention, even when the French experienced a devastating defeat at Dien Bien Phu in the spring of 1954. Following that battle, an international conference was called and held at Geneva, Switzerland. A cease-fire was arranged. Also as part of the...