[Roa_Aoife]

One major thing that has been left out: Tolkien repeatedly stated that LotR was not allegorical in anyway. He meant it to be enjoyed for what it was, not to fuel political statements.
That said, I think war is an evil, but a nessary one. It's not pleasant, pretty, or glorious, but it can be honourable and courageous, and sometimes the best course of action. In the last book, we see Eowyn and Merry striving to defend the people the care about, contrasted with Denethor, who was cowardly and refused to fight.
I don't know much about World War I, but action World War II was entirely necessary. I regret tha America did not get involved sooner. Hitler was an evil that needed to be stopped. Innocent people were being killed, and somethings, no matter what you say, are just wrong. I'm not saying that anyone had wholly pure reasons for going in, but what came about was for the better. It also serves as a reminder to future generations about the evils of war, and how for such evils can go.