Historically, successful reintegration of war veterans into civilized society has been an enduring concern of nations. Data from the National Vietnam Veterans Readjustment Study were used to develop and evaluate an etiological model of postwar antisocial behavior. Two initial models specified causal paths among five sets of variables, ordered according to their historical occurrence: (a) premilitary risk factors, (b) military traumas and disciplinary actions, (c) the homecoming reception, (d) postmilitary PTSD and substance abuse, and (e) postmilitary antisocial behavior. PTSD and substance abuse were omitted in one model and included in the other. The initial models were refined and then cross-validated, leading to the specification of replicated models with highly satisfactory fit and parsimony. Comparison of the two models suggested that (1) premilitary experiences and behavior exert the largest effects on postmilitary antisocial behavior, and that (2) PTSD plays a necessary mediational role for the effects of war-zone traumatic exposure on postmilitary antisocial behavior.