The prospect of domestic bioterrorism.

Would domestic terrorists use biological weapons?1 The conventional wisdom among experts has been that terrorists “want a lot of people watching, not a lot of people dead” and are unlikely to turn to weapons of mass destruction.2 A new school of thought proposes that improved technology has made biological attacks resulting in hundreds of thousands or millions of deaths all but inevitable. While terrorists are increasingly interested in weapons of mass destruction, proponents of the latter view exaggerate the threat. Using biological weapons to create mass casualties would require more than having biological agents in hand. The terrorists would need to disseminate the agent, which presents technical and organizational obstacles that few domestic groups could surmount. In addition, relatively few terrorists would want to kill millions of people, even if they could. For most terrorists, the costs of escalation to biological weapons would seem to outweigh the benefits. Most modern terrorists have had substantively rational goals, such as attaining national autonomy or establishing a government purportedly more representative of the people’s will. Escalating to such frightening weapons would result in a massive government crackdown and could alienate the group’s supporters. Biological weapons are also dangerous to produce. A number of Aum Shinrikyo members reportedly damaged their own health while working on biological agents. Additionally, some terrorists may perceive moral constraints.3 Candidates for successful use of biological weapons represent the intersection of three sets: groups that want to use these weapons despite formidable political risks; groups that can acquire the agent and a dissemination device (however crude); and groups whose organizational structure enables them to deliver or disseminate the agent covertly. The intersection of these sets is small but growing, especially for low-technology attacks such as contaminating food or disseminating biological agents in an enclosed space. Major attacks are also becoming more likely. In the sections that follow, we consider eroding motivational, technical, and organizational constraints.