This article proposes a developmental psychological model of the conditions that favor terrorist actions which represent publicly discernible goals ascribed to a political religious cause. Entrenched cognitive simplicity in one key ideological domain (religious or political) is coupled with behavior reflecting the capacity for far greater complexity in other domains (organizational skills, planning problem-solving). Scholarship and theoretical explanations of terrorism have been in demand and have increased since the attacks of September 11, 2001. Using developmental and ecological dailies as a framework, one can create a dynamic model of the kinds of situations that allow communities to see the creation of terror and destruction as a necessary, defensible, and even prosocial activity. This model includes attention to the development of leaders, volunteers, communities of support, and the relationships between communities of support and society at large. The model seems to be a generally good fit for several areas were less powerful groups have engaged in non-state-sponsored terrorism: Spain's Basque area, Northern Ireland, Chechnya, and the Northeast (Tamil) area of Sri Lanka. In several of these conflict situations, one or more leaders of the less powerful group have shown developmental shifts toward the ability to manage increased complexity in leading, or considering, the actions of the group. However, progress in the area of managing a complex organization does not necessarily lead to progress in relation to considerations of political religious ideology. Ability and willingness to negotiate for the sake of peace requires higher levels in the area of ideology, as well as their area of organizational competence. Notes