National security is a basic responsibility of national governments, but it is also intangible. What can economic analysis contribute? Benefit-cost analysis has rarely been applied because of the ambiguous and commons nature of the benefits. Our group at the University of Southern California’s Center for Risk and Economic Analysis of Terrorism (CREATE) has worked to elaborate and apply economic impact analysis to describe the expected losses from various hypothetical terrorist attacks. Our innovation has been to add a spatial dimension to operational inter-industry models.