According to this article, the most powerful lens through which to view terrorist behavior is that of group, organizational, and social psychology, with a particular emphasis on collective identity. "It will require decades to change the culture of hatred and violence. In this struggle, the moral high ground needs to be maintained, for example, by strengthening the rule of law and exemplifying good governance and social justice. To depart from these standards is to lower ourselves to the level of the terrorists and to damage liberal democracy."
U.S. Department of State: http://usinfo.state.gov/
Foreign Policy Agenda (May 2007), v.12 no.5