Survey respondents in fourteen countries representing 62% of the world's Muslim population indicate that approval of Islamist terror is not associated with religiosity, lack of education, poverty, or income dissatisfaction. Instead, it is associated with urban poverty. These results are consistent with the thesis that Islamist terrorists obtain support and recruits from the urban poor, who pursue their economic interests off the market in politics in collective groups. These groups compete over state rents, so a gain for one group is a loss for another, making terrorism of members of out-groups rational. The rise of militant Islam can be attributed to high rates of urbanization in many Muslim countries in recent decades, which fosters violence as rising groups seek to dislodge prior groups entrenched in power. Rising group leaders also compete over new urban followers, so they promote fears of out-groups and package in-group identities in ways that ring true for the urban poor. Because many of the urban poor are migrants from the countryside, popular packages are those which identify with traditional rural values and distinguish enemies as those associated with urban modernity and the secular groups already in power. Imams have an incentive to preach want audiences want to hear, so a mutated in-group version of Islam-Islamism-struck a chord in several large cities around the globe at the same time. With globalization of the media, in many developing countries the West is widely (albeit wrongly) perceived as an inimical out-group associated with urban modernity. The best political strategy to limit support and recruits for Islamist terrorist groups is to enhance the economic opportunities available for the urban poor, and to provide them the needed services, such as access to health care and education, that many currently obtain from Islamist groups.