Most of the stories I write revolve around war. The central plot of my current comic West involves a war between the living and the dead. It is set in an alternate universe, not Earth but something similar.
While the war in West is a major element of the story it's certainly not all that it's about. It's just a framework: a basic underlying mission that keeps Jed on course. There always something to be done towards solving the war, but sometimes other priorities get in the way. All throughout his journey minor missions crop up. Like 'how do we get from A to B?' and 'why is everyone here so sick?'. In most cases the answers to these questions relate back to the war he is trying to stop, but not always. Sometimes the latest problem is quite mundane like 'Why is this person so mad at me?' or 'How do I tell x what I really want to say?'.
Alternatively, in another story of mine, The Scabbard Altar, war is the main source of contention for all the characters. Some characters support it and others don't, even members within the same team. Some characters aren't interested in the war at all, just preservation of their lives and traditions. Others are exploiting the war to get ahead. Relationships between characters come into play, but the war is at the heart of it and at the fore front of almost everyone's minds.
War is a common device in the fictional world but the importance of it and its overall effect on your story is entirely up to you. I'd certainly agree with @aronthemason and his comment on doing your research, though. If you're going to base your story on history do it as best you can, as much for immersion as credibility.