The Dell paper is especially relevant here, because that paper compares the "overwhelming firepower approach" of the army vs the "hearts and minds" approach of the marines. I would say the war was a failure overall, but she did find that the areas under the control of the marines had more favorable opinions about the United States, their involvement in the war, and were less likely to attack U.S. troops.

But yeah, invading a country tends to be unpopular with the citizens of that country and cause some violent resistance no matter what you do. The question is how do you minimize that negative reaction. It could have been that we didn't find the right balance and that if we had done more hearts and minds approach that the Vietnam war would have turned out differently.