I just finished reading David Grossman's "On Killing;" he refers to a book Bob Greene wrote. The columnist thought the spitting was legendary rather than factual. He solicited letters from vets, and over a thousand testomials letters persuaded him otherwise.

BTW, I highly recommend Grossman's book. Not for simpleminded partisans of either side. The core argument, and it's well defended, is that there's very little killer instinct (except for the 2% of us who are sociopaths) -- which is why nations take so much trouble training adolescents to overcome their innate reluctance to kill. The spitting, even if its incidence was overstated, nonetheless stands for the lack of re-integration ceremonies and rituals for returning 'Nam vets -- an element, in Grossman's view, of the complex that made their postwar experience much more traumantic than that of many earlier veterans who had experienced, qualitatively, quantitatively, more horror.

Adam