World War II soldiers joined for the duration. A soldier may have come into
combat as an individual replacement, but he knew that he would be with his
unit for the rest of the war. He was very invested in establishing himself
with his newfound unit, and those who were already in the unit had equal
cause to bond with this individual, who they knew would be their comrade
until the war was over. These individuals developed very mature, fulfilling
relationships that for most of them have lasted throughout their lives. In
Vietnam most soldiers arrived on the battlefield alone, afraid, and without
friends. A soldier joined a unit where he was an FNG, a "f'ing new guy,"
whose inexperience and incompetence represented a threat to the continued
survival of those in the unit. In a few months, for a brief period, he
became an old hand who was bonded to a few friends and able to function
well in combat. But then, all too soon, his friends left him via death,
injury, or the end of their tours, and he too became a short timer, whose
only concern was surviving until the end of his tour of duty. Unit morale,
cohesion, and bonding suffered tremendously. All but the best of units
became just a collection of men experiencing endless leavings and arrivals,
and that sacred process of bonding, which makes it possible for men to do
what they must do in combat, became a tattered and torn remnant of the
support structure experienced by veterans of past American wars. Lt. Col.
Dave Grossman, On Killing
http://tipyomi-sender.appspot.com/showtip/Sheepdog%20Tip%20of%20the%20Day/During%20Combat/183