Attribution, along with prosecution or retribution, is one of the greatest deterrent tools against terrorism. Exclusion, the opposite of attribution, is equally important in the highly charged environment after a terrorist event. The materials and techniques used for attribution may involve both classified methods and information that hasn’t had domestic or international exposure. The military looks for the solution to a problem in doctrine, operations, and technology. The two fundamental issues that arise regarding doctrine are what capabilities are to be revealed for attribution and with whom to partner in the activity. One important issue to be addressed before the event is whether to pursue information and attribution in a manner that would preclude prosecution as opposed to retribution. Several steps need to be taken operationally before an event occurs. The first step is to establish and train the organizations that will execute the attribution process. Another step is the frank and honest education of political decisionmakers. Preparing to communicate with the public is an essential step in operational preparation. Training and resourcing capabilities involves the creation of a common approach to dealing with events of different kinds. Technology for a nuclear case involves determining the sophistication of the device and acquiring samples. If forensic determinations can be made, the result of the device characterization could be compared to the databases of known weapons materials, credible capabilities, and the sophistication of possible weapons states or actors. Technology for the biological case will be detection by the medical surveillance processes of the public health care system. If samples of the agent are recovered, its non-biological properties may be valuable in identifying the potential actor. Recommendations include establishing unambiguous ownership of the forensic responsibility with the Federal Bureau of Investigation; establishing oversight and attribution panels for both the nuclear and biological forensics efforts; and examining legal issues.