After listening to this song twice and making out the words during the second time around (with the help of hearing Vienna's explanation about the song), I'm pretty sure that the song is titled Antebellum.
The chorus roughly goes like this (I don't recall the words exactly):
i know the borderlines are true between us
keep your weapons down, keep the wounded safe
i know our antebellum innocence is
never meant to see the light of our armistice day
Though the war symbolism is everywhere from the lyrics to the marching drum beat, the song is actually about two people who love and care for each other very much but realize after being together for awhile that the best thing for the both of them is to be at a distance. Thus the lines at the end:
you'll stay here
i'll go home
seasons keep on marching
you'll go home
i'll stay here
This song is currently fighting with Kansas in my head for the title of saddest song ever.
(Though I suppose you can argue that this song isn't entirely depressing, unlike Kansas.)