During the Vietnam War, because the U.S. never officially declared war on North Vietnam, the North Vietnamese argued that all captured U.S. soldiers were therefore enemy combatants and thus not P.O.W.s and the Geneva Convention rights did not apply. Therefore, any captured U.S. soliders could be held indefinitely without charges, could be tortured for information about troop placements, leadership, strength, and movements, and did not have to be included in prisoner exchanges. Sound familiar?
The shoe is on the other foot now, and it fits just as poorly.
I also learned that leading the charge in the Tet Offensive was possibly the Viet Cong's biggest mistake--they were beaten back so badly that after that, they ceased to be a significant player in the war; almost all conflict after that point was with the regular North Vietnamese army. In other words, this was one of the biggest successes by the allies of South Vietnam, and it should have been possible to build on that momentum and quickly either get to a stalemate condition (a la Korea) or to bring a strong hand to the treaty table. Unfortunately, apparently in large part due to U.S. media & public emphasizing the losses rather than the gains, there was no such momentum on the home front, protests against the war grew significantly during that time, soldiers hearing news from home were disheartened, and the administration (who were frequently micromanaging everything from afar) reacted to their gains as if they had been the losses being reported in the media, were hesitant to push any further and instead went looking for a way out; this likely resulted in prolonging the war by several years. (Not the only thing to do so, but an element that isn't widely reported these days.) Thus, it is most certainly possible for rampant negativism in the media & the general public about a current conflict to undermine our troops abroad and make things worse than they would have been if detractors weren't as vehemently vocal. That's not to say our current situation is identical to where we were after the Tet Offensive, but there are certainly parallels worth keeping in mind.
Feudalism: Serf & Turf