It turns out that it is quite hard to train soldiers to kill.
Former US army ranger, and later professor of military science at Arkansas State University, lieutenant colonel Dave Grossman has written two books dealing with the psychology of inflicting lethal violence: On Killing – The Psychological Cost of Learning to Kill in War and Society (1995); and (with Loren Christensen) On Combat: The Psychology and Physiology of Deadly Conflict in War and in Peace (2004).
Grossman…