Scott Oden, over on his blog, posted the question "As writers, what do our characters say about us?" and more specifically, why write about the soldier more than other types of characters? Many Fantasy/SF/Historical writers DO tend to choose soldiers as main characters. What attracts us to them? Why a soldier and not a ditch digger or cheesemaker?
I think one of the attractions of the soldier theme besides the obvious dramatic background of war or potential war is the underlying sense of a soldier working for something outside himself. Soldiers can't be concerned with ME, because too many other people are relying on them; superiors, underlings, governments, civilians, the entire free world…
This is the kind of situation where you can really see what a character is made of. If ordered to slaughter a village by higher-ups, would your character do it? As a soldier, saying 'Screw you, I don't feel like it" doesn't fly. Soldiers take oaths that imply legal and moral obligations. The penalty for failing to fulfill those oaths can be steep. Imprisonment, or even death. Soldiers are constantly weighing the greater good, individual freedoms, and personal ethics against each other. They are master jugglers. Knowing that you can't please everyone is inherent in their position, but how to preserve your own sanity and morals while still doing the job you signed up to do?
There aren't a lot of privates in the fantasy/sf world. Face it, privates are boring. You do what you are told, no real moral decision making on your part. The big choices are made for you, and if you disagree, too bad. You are a private, good for cannon fodder and grunt duties, but little else. You don't have the training or expertise to BE much more. Not yet. Until you prove yourself worth it, the military isn't going to waste a lot of time or resources on you. There is very little a private can do to affect change. Most characters in novels that start out as privates don't stay that way long. They are promoted to some position of authority, cherry-picked for a special forces kind of operation, or turn traitors.
Besides, do you really want to read about some guy that digs latrines for 8 hours, stands guard duty and sleeps when not busy being scared shitless by battle? I don't. I want to read about the people that have to make the life and death decisions, the ones who agonize over the morality of defending one part of their world at the expense of another. The guy (or gal) who keenly feels the death of everyone under his command, but doesn't let it stop him from doing his duty, because that is what it all comes down to in the end. Duty. Honor. Country. Or some form there of. A sense of belonging to something bigger than yourself.
That can be very seductive. It can also be corruptive. While you may belong to this unit, the unit of soldiers also belongs to you. Responsibility and temptation all in one. A strong military leader can change the course of countries. The decision making capability in the hands of one person is what attracts me to the soldier as fictional character. As a writer, Scott wants to explore what he missed by not being in the military. As a writer who was in the military, I want to reexamine my decisions and actions through my fictional characters. Are they still valid? Knowing what I know now, would I do the same thing? This is my second chance. In real life, you don't get too many of those.
C.A. Brewer, Captain (Ret.) US Army Corp of Engineers.