The vast amount of people killed in modern wars would be from artillery and aerial bombardment.A lot of men who could not possibly kill an opponent in close quarters combat probably have no problem killing thousands from a distance.As an aside,and speaking of the Vietnam War,during the period 1974-75,more American Officers were killed by their own men than the enemy,the practice was called fragging and was used to rid combat weary troops of inexperienced,newly commissioned officers.Also during 1974-75,more US servicemen died of drug overdoses than were killed in action.
