An interesting topic. What's your stance?
Difficult to say. If we had bombed them with nuclear weapons, we might have 'won,' or if we would have toughed it out. This also depends on your definition of victory; Vietnam lost 3 to 4 million, the us lost a sixtieth to an eightieth of that. So, as far as deaths go, we 'won.' And because we were in their land, we arguable didn't 'surrender,' we pulled out.
Was Vietnam really an unwinnable war?
Once again, it depends on how you define 'victory.' By your definition, the one with the stronger will will win, if they aren't wiped out.
What makes a war unwinnable?
If another declares it first. I'm a pacifist by nature; if fighting can be avoided, it should be.
On which conditions should a country be able to declare war?
See 'what makes a war unwinnabe.'
What are the primary determining factors in war?
Propaganda is a large part of wars. If we believe we are right, we will continue to fight, ditto if we think we can win. If not, moral is severely hurt, and troops will not fight as well.
How does human psychology influence war?
"It may be that the universe is just one of those things that happens from time to time."
- Edward Tryon