"I think you misread the situation. In the abstract, the elite had no particular reason to want a war. But once the conflict formed up, it was impossible for them to get out of without losing prestige. Why was prestige such a precious commodity? Because they are an elite, and a successful challenge was impossible. Of course they had no desire to govern Vietnam directly, or to occupy it in perpetuity. But above all, they had to defeat the challenger."
Yes, and the same could be said of Afghanistan. If anyone on this list has not read Orwell's "Shooting an Elephant," now's the time.
Joanna