Frederica, you write , "One way that war is hell, and something that may be a clue to some mysterious spiritual truth, is that soldiers who kill are much more traumatized by that than by any injuries they sustain." That’s certainly been the conventional wisdom since Vietnam, and I want to believe it, for exactly the reason you go on to mention: "God has put something in us that revolts at killing, even in a cause we believe is just."
But do we have any actual evidence that soldiers are traumatized much more by killing than by their injuries? Does Homer, for instance, ever observe it? Do the Books of Joshua and Judges? I’m not sure I trust the MacNair report you mention as true for all soldiers at all times (which is what your claim of human nature, something God put in us, would require).
In that tremendous first story about Major Brown in The Club of Queer Trades , G.K. Chesterton claims that having been to war ever after makes a man gentle. That’s probably just Chesterton blowing smoke, but it does suggest that the post-Vietnam claim of traumatized and violent veterans could have been born less from the facts than from the anti-Vietnam protesters’ desire that the war be seen as unreservedly evil.
It’s true that some medieval canons prohibited even repentant soldiers and murderers from becoming priests¯but it’s possible to take that as making a metaphysical claim about the effect of spilled blood, rather than a psychological claim, for the same canons also stopped butchers from becoming priests. As I say, I want to believe that you’re right, but maybe here is a place where Christianity brought something new into the world. Maybe it is faith that instructs us to see a metaphysical truth that human nature might otherwise be blind to¯and thus we have yet another of the tensions that you observe in the Christian soldier fighting in even the most just cause.