Deviant Cohesion and Unauthorized Atrocities: Evidence from the American War in Vietnam

Why do soldiers engage in unauthorized atrocities? This article explores this question by analyzing the use of postmortem mutilation by American soldiers during the Vietnam War. I show that such acts were remarkably frequent, despite being explicitly prohibited by military policy, and argue that individual-level variation in participation in such violence is explained by social dynamics within military units. Soldiers used mutilation mostly as a means of avenging enemy atrocities or deaths among comrades. Revenge motives were stronger when soldiers shared particularly strong social bonds. Whether these motives resulted in unauthorized atrocity, however, depended on the extent to which discipline was maintained within military units. In units characterized by “deviant cohesion”—strong social ties and weak discipline—informal combatant norms diverged from organizational policies and promoted unauthorized atrocities as a unit-level practice. Evidence for this theory comes from a combination of archival sources and survey data gathered from a representative sample of Vietnam War veterans. A case study of a single Army unit illustrates the mechanism implied by the theory.