Suicide terrorism is rising around the world, but the most common explanations do not help us understand why. Religious fanaticism does not explain why the world leader in suicide terrorism is the Tamil Tigers in Sri Lanka, a group that adheres to a Marxist/Leninist ideology, while existing psychological explanations have been contradicted by the widening range of socio-economic backgrounds of suicide terrorists. To advance our understanding of this growing phenomenon, this study collects the universe of suicide terrorist attacks worldwide from 1980 to 2001, 188 in all. In contrast to the existing explanations, this study shows that suicide terrorism follows a strategic logic, one specifically designed to coerce modern liberal democracies to make significant territorial concessions. Moreover, over the past two decades, suicide terrorism has been rising largely because terrorists have learned that it pays. Suicide terrorists sought to compel American and French military forces to abandon Lebanon in 1983, Israeli forces to leave Lebanon in 1985, Israeli forces to quit the Gaza Strip and the West Bank in 1994 and 1995, the Sri Lankan government to create an independent Tamil state from 1990 on, and the Turkish government to grant autonomy to the Kurds in the late 1990s. In all but the case of Turkey, the terrorist political cause made more gains after the resort to suicide operations than it had before. Thus, Western democracies should pursue policies that teach terrorists that the lesson of the 1980s and 1990s no longer holds, policies which in practice may have more to do with improving homeland security than with offensive military action.I thank Robert Art, Mia Bloom, Steven Cícala, Alex Downs, Daniel Drezner, Adria Lawrence, Sean Lynn-Jones, John Mearsheimer, Michael O'Connor, Sebastian Rosato, Lisa Weeden, the anonymous reviewers, and the members of the program on International Security Policy at the University of Chicago for their superb comments. I especially thank James K. Feldman and Chaim D. Kaufmann for their excellent comments on multiple drafts. I would also like to acknowledge encouragement from the committee for the Combating Political Violence paper competition sponsored by the Institute for War and Peace Studies at Columbia University, which selected an earlier version as a winning paper.