Hello Gentlemen

I am participating on a colloquium at the university about the American Military from 1917 to the War in Afghanistan. Today we talked about the war in Vietnam and the problems that arised within the American troops (racism, social problems, refusal to obey orders, killing of officers etc.). We wondered whether the US Armed Forces have conducted a survey among the soldiers as they did during the Second World War or the Korean War for example to study the motivation of the soldiers or their behaviour in battle as had been done by Samuel Stouffer, or S.L.A.Marshall. The only survey I know of is the study of Douglas Kinnard about American generals in Vietnam (The War Managers, NY 1977).
Does somebody know of a study that covers questions similar to those of Stouffer or Marshall for the lower ranks and soldiers of the US Army?
So I am from Switzerland (this said I hope this excuses some of my ignorance about and my bad English). I would be grateful if somebody could help me. Thanks in advance.

Regards PB