This song is not about war. He uses war and death as metaphors. The song is about a relationship between him and a girl. When he says "so march with me if you think there is any hope for us" he's saying if you believe our relationship can't make it come with me and he tells her "I've been thinking these visions are a sign, so hold on don't let go", he's saying that they're meant to be together and to have faith in him. Later he says that he's "been dreaming of leaving everything behind" and taking her with him but in order for them to start fresh she has to tell him the truth and her secrets. So when he says "bring out your dead", he wants her to reveal the "skeletons in her closet". He wants to know everything so they can't start fresh and be together without worrying about anything else.