Comment by kstenerud

In this particular case, the North was in the right. As far as they were concerned, the Americans were just one more occupier in a long line of Western occupiers. And even though the Americans didn't intend to become occupiers, that's ultimately what happened (a theme that's repeated itself many times). The Americans and the Vietnamese were fighting different wars with each other. So the North pushed out the occupiers and liberated their country.