Why do people decide to sacrifice their own lives - the totality of their self-interests - in acts of extreme violence against others? A standard assumption of policymakers and researchers on war and terrorism is that decisions to support or oppose warfare are made in an instrumentally rational manner and thus driven by cost-benefit calculations. But war in general, and suicide terrorism in particular, arouse humans’ most noble sentiments and worst fears, and rarely, if ever, derive wholly from reason and rational calculation. This challenges the claim that war is basically “politics by other means.” In previous experiments carried out across different cultural and political contexts, with political leaders and larger populations in the Middle East and elsewhere, we found that decisions to support or oppose political violence could be framed as moral dilemmas that lead to dramatic insensitivity to instrumental outcomes. Other research supports the notion that extreme group violence is primarily a male occupation driven across human history and cultures by an evolved aptitude for parochial altruism as a moral virtue.