The following text is from a response at Talk str8 (talk straight). 

A.G.:  Kids always seem interested in the question, "Have you ever killed anybody - like in the war?" I've answered similar questions in this column before. I must tell you that killing another person is a terrible thing - no matter what the circumstances. It is a thing that you will always carry with you. In a war, you are killing the enemy. This is a person you are permitted to kill. You are supposed to kill "enemies." Even if it seems alright at the time - killing another person remains a problem forever. It is a thing that must be done but can never, ever be OK. I have known soldiers who desperately wanted to kill an enemy. These people are very frightening.   I have heard men boast about killing helpless women and children. These are the people who have enormous problems trying to readjust to civilian life. While necessary, killing and injuring others is never a good thing. There are also different kinds of killing. There is hand to hand killing (combat & support units), killing at a distance (combat & support troops),  killing remotely (aircraft, ships, artillery, etc. ), killing by decision (NCO's, officers, planners, and commanders). A veteran may hesitate or dodge giving you an answer to this common and simple question because the answer is anything but "simple".

I am going to get long winded here. Please bear with me.

Being a soldier in war time is extremely difficult. Our "country" (The American government and its people) send us out to do horrible things to others as well as ourselves. It asks us to be willing to die on the basis of a simple order from anyone one step above us in rank. It offers almost nothing in return - a small income, a little insurance, and the promise of a little help later getting jobs, education, and housing - if we survive. After Vietnam, even much of this was denied veterans (not officially - of course.) If a soldier is wounded or handicapped (a common occurrence), assistance and health care are provided under conditions few civilians would ever be asked to tolerate. I was and remain incredibly proud of the young men (very few women at the time) who were FORCED to serve AGAINST THEIR WISHES in Vietnam. They served with honor, bravery, and with admirable decency along side career soldiers (men and women) of the highest quality. They killed. They destroyed. They made mistakes, had accidents, and committed "atrocities"  which resulted in friendly, enemy, and non-combatant deaths.  All of war is an atrocity. To make rules and draws lines is an idiot's game. This has, and will always happen under war time conditions. The very civilians (our Government) who send soldiers into impossible situations later presume to sit in judgement of their actions in combat assisted by senior officers and commanders who can no longer see or admit that they would have reacted in a similar manner under similar conditions. An 18 year old forced to fight in a war againts his will and absolutely convinced he will be killed or maimed (much like modern gang members) lives by an unwritten code of conduct. Consequences and punishments become irrelevant. The evaluations of superiors are meaningless. A conscript in war time fights for his "buddies", his team, his brothers, and for the right to control his immediate destiny - small as this might be. He will gladly die for an NCO or officer he trusts and may very well kill or passively resist one he doesn't. It is his right under combat conditions. I have also seen soldiers I thought were "OK", engage in suicidal behavior which might easily have been interpreted by an outsider as selfless bravery.  They consciously or unconsciously seemed tired of going on and - it was my impression - asked the enemy to end it for them.

Peace time is a completely different situation. Limited engagements and brief "wars" rarely involve war time psychology and may actually lead to an even MORE CONFUSING mix of war time/peace time mental states.

War time psychology only exists under protracted, inescapable, convincingly lethal conditions where hope of survival has been surrendered. It is very effective. It produces what may appear to be valor. It exists for combat and support people in conflicts like Vietnam where all areas are vulnerable and where troops operate in and out of combat zones on a daily or even an hourly basis.  Leading men under these conditions places entirely unreasonable demands on the NCO's and Officers in direct command of these troops.  I have the greatest admiration for those who do it successfully. The failures may well be left in the field. Sometimes the failures are saved by superiors who have the wisdom to recognize a situation about to meet a "field" solution and remove them from harm's way. Well led soldiers under these conditions are truly formidable.

I have tried to state in a few paragraphs what could easily fill volumes. I hope it makes some sense to you.