The USA was so committed to the containment of Communism that direct conflict was inevitable

American intervention in the conflict in Vietnam started on its inevitable path ever since the closing months of the Second World War. The fate of Indochina was discussed (but not a high priority) at the Potsdam Conference, which began on 17 July 1945. The settlement called for the division of the country at the 16th Parallel in which the Allies (mainly the British) were to occupy the South and to have Chiang-Kai-Shek's Nationalist forces occupy the North …

…and political instability in the south and the Gulf of Tonkin incident made escalation by the USA inescapable as it would cost them to lose face to the international community and lose their resolve for containing what they believed was a very serious and major Communist threat which would not only mean the fall of their neighbouring countries to the Red Terror, but would also derail American interests and their ideals of a 'Free World'.