I'm not too sure if this has been discussed before, but if it has, then apologies.
It is 1945. The Second World War had just ended and the French are fighting to reclaim control of Vietnam from the Vietminh. The French -backed regime under the puppet Emperor Bao Dai is but ineffective and corrupt. In light of this, Charles De Gaulle asked Prince Vinh San (aka Emperor Duy Tan) to return to Vietnam to take over from Bao Dai. Remember that the prince was still quite a popular figure in Vietnam for having led a rebellion (which failed) against the French in the midst of the First World War. He was supposedly one of the few people who could provide an alternative to Ho Chi Minh's brand of nationalism. Unfortunately, he died in an air crash in 1945 in Central Africa on the way back to Vietnam.
Now let's say that the plane crash did not take place and Duy Tan arrives in Vietnam in one piece. How is this going to affect the politics of Indochina and possibly the rest of Southeast Asia at this point? I was thinking that it may still result in a North-South Vietnam divide but the South Vietnamese state this time may be stronger. I mean, that's pretty much assuming that Duy Tan does not make the mistakes of Diem and Thieu in the RVN period. What do you think?