The effects of war-induced anxiety and mental distress on individuals and groups can either be mitigated or exacerbated by ‘humanitarian action’. This paper focuses on two key factors that protect the mental well-being of war-affected populations: organized displacement or assisted relocation; and coordinated humanitarian aid operations that are responsive to local needs. Qualitative data from two internally displaced person (IDP) camps in Eritrea are presented. Analysis of these data serves to substantiate and refine a working hypothesis: that social support of the right type, provided at the right time and level, can mitigate the worst effects of war and displacement on victims/survivors. An integrated model of psychosocial transition is suggested. The implications of this approach for humanitarian policy and practice are discussed in the wider context of current debates and lamentations of the ‘humanitarian idea’.