Terrorism is designed to change minds by destroying bodies; it is a form of costly signaling. Terrorists employ five primary strategies of costly signaling: attrition, intimidation, provocation, spoiling, and outbidding. The main targets of persuasion are the enemy and the population that the terrorists hope to represent or control. Terrorists wish to signal that they have the strength and will to impose costs on those who oppose them, and that the enemy and moderate groups on the terrorists' side cannot be trusted and should not be supported. Each strategy works well under certain conditions and poorly under others. State responses to one strategy may be inappropriate for other strategies. In some cases, however, terrorists are pursuing a combination of strategies, and the response must also work well against this combination.
This article is the second installment in a collaborative project, and the order of the authors' names was determined by alphabetical order.