Green soldiers arrive at their first battle unprepared. They lack trust in their comrades and their leaders, who in turn lack trust in them. Their training is incomplete. The soldiers who came before them have learned and practiced field expedients that no Army training prepared them for. Yet, they must survive. Thus, they are, in the best of circumstances, placed with battle-hardened troops until they are tempered under fire.
Survival is its own reward. Green troops most often greet its arrival with 'the shakes.' The adrenal gland continues pumping 'fight or flight' hormones into the system long after the bullets have stopped flying and the shells have stopped bursting. Euphoria washes away fear. Victor and vanquished alike celebrate life. Innocence is lost.
Battle-hardened troops react with exhaustion. Their automatic reflexes have adapted to battle, the adrenaline abates more quickly, and they become annoyed with the antics of the first-timers. Victories are not celebrated nor losses lamented with as much enthusiasm as they once were. Lost comrades are more quickly forgotten. Innocence is forgotten.
In the end, everyone knows that they risk death when they enter the battlefield. Only after experiencing their first battle, can they come to accept it. All who survive, survive with Post Traumatic Stress Syndrome at some level. "Battle-hardened" is just another way of saying "battle-scarred."
Veteran units had the luxury of assigning replacements to fight beside experienced infantrymen. The 9th Infantry Division arrived in Vietnam, virtually en masse. Just before I joined them they infused with other infantry units around the country - trading inexperienced soldiers for combat hardened men - so that the green troops could have some experienced men to "steady" them in their first trials by fire.
I can't lie here. I wasn't a combat soldier and I never participated in a fire fight. I was sniped at on a couple of occasions and had rounds fired at helicopters that I was riding in. The truth is that it's probably a good thing that the Army didn't make me a combat officer. Someone must have looked at me and decided that I was going to get someone killed if I led men in combat. As it turns out, I got mad when someone shot at me and I made some stupid decisions. Of course, that occurred after I received my second Dear John from the same girl. Like I said, I was stupid.