If you live after giving up on the things you want to do and the world around you doesn't sparkle, it's the same thing as being dead. If you don't give up, even if it's short, it'll be a fantastic life!
If you want to stand with your own will, you don't have any other choice than to let the illusions you have lost remain in the ideals you were following in the past.
Plainly speaking war is nothing other than "wanting to impose your beliefs on your opponent." It only happens for that reason. You don't have any exception to that rule.