The threat of terrorism has focused the attention of the United States on domestic preparedness. Although the likelihood of a domestic terrorist attack may be relatively low, the country is nonetheless preparing first responders, local, state and federal officials, and the public on what to do and what to expect should one occur. Lawyers have only recently begun to consider the issue of domestic preparedness. Any steps to improve preparedness must, of course, involve an assessment by the proper legal authorities to determine their lawfulness and legitimacy. This paper addresses two significant legal problems with the U.S. domestic preparedness program. It initially analyzes the doctrinal difficulties inherent in defining a terrorism incident. It then considers -- as a distinct subset of terrorism -- the particular problem of biological terrorism. Given the nature and impact of biological terrorism, it will likely impact our present legal regime in ways that are unique (as compared to other forms of terrorism) and risky. This paper ultimately argues that the concerns with legal preparedness too often mask the more difficult policy and political considerations that must be evaluated in any counterterrorist policy.