One of the underlying purposes of this paper is to provoke thinking about the interplay between the regulation of radioactive materials and the risk of their use in an radiological weapon (RW). Also considered in this paper are the types of RWs that a terrorist might use, the nature of the threat and danger posed by the various types of RWs, the essential elements that must be considered in responding to the terrorist use of an RW, and what steps may need to be taken a priori to minimize the consequences of the inevitable use of an RW. Because radiological dispersal devices (RDDs) have been the focus of so much recent concern and because RDDs are arguably the most likely of RWs to be used by a terrorist group, a major focus of this paper will be on RDDs. Radiological weapons are going to be used by some individual or group, if not this year then next year, or at some time in the foreseeable future. A policy of focusing resources solely on prevention of their use would leave any government open to significant economic disruption when the inevitable use occurs. Preplanning can limit the injuries, property damage, and economicmore » losses that might result from the use of an RW. Moreover, a combination of efforts to prevent and to minimize the impact of RWs may significantly discourage potential users. The dangers from RWs can be dealt with while society continues to enjoy the benefits of nuclear technology that were promised under Atoms for Peace. However, some restructuring of our use of radioactive materials is necessary to ensure that the current and future uses of radioactive materials outweigh the potential disruption caused by misuse of the materials in RWs.« less