Beyond that, in many ways, the British are directly responsible for the Vietnam war. They raced East from Burma into Vietnam specifically to put down the Vietnamese revolt, armed 1000 French, who led a successful countercoup.The focus in 1945 was on Europe. The British in particular were keen on rebuilding a strong France as they feared America would return to isolationism. Much like Korea the "border" at the 17th parallel was the demarcation between the British disarming the Japanese in the south and the Chinese doing so in the north. The British were also keen on "not one scrap of British territory" so the French Empire was logical corollary . Despite the commitment to free the Philippines the US had little appetite for decolonization. The State Department was pale, male and Yale.
I have read that Ho sought US recognition of his movement. IT might have been a different world.
There was a Vietnam, and the British toppled it, leading to everything that came after.
FDR wanted Vietnam to be an UN trusteeship. Had FDR lived and Casey not toppled Vietnam, he might have recognized Vietnam with UN intervention to ensure fair elections. Had Casey not gone into Vietnam, Truman might have eventually recognized Vietnam (Chiang's government did).