Testifying in 1971 as part of the Winter Soldier Investigation, a war crimes hearing sponsored by the Vietnam Veterans Against the War, psychiatrist Robert Jay Lifton distinguished the American war in Vietnam from other conflicts:

There’s a quality of atrocity in this war that goes beyond that of other wars in that the war itself is fought as a series of atrocities. There is no distinction between an enemy whom one can justifiably fire at and people whom one murders in less than military situations.

Concluding this thought by reflecting on the experience of soldiers and veterans, Lifton observed, “Now if one carries this sense of atrocity with one, one carries the sense of descent into evil.”