For completeness the timeline should go back to the origins, which was the 1945 struggle to gain independence which was largely ignored by the Western Powers and which led to Ho Chi Min pleading with them to provide guarantees that the French would not get their old colony back based on their support against the Japanese during WWII.
Their ignorance of the wish of the Vietnamese to determine their own future after WWII directly led to Ho Chi Min asking the Soviet Union for support and assistance, which in about 1949 they finally agreed to and effectively funded and armed the Viet Minh.
I blame Harry Truman myself.
http://en.wikipedia.org/wiki/Vietnam...ground_to_1949
Oooohhh sorry, this one is a bit long for ADD sufferers.