We describe an ongoing effort to develop a decision aid to give military planners, from battle planners to psychological operators, a handle on the nature and behavior of populations in an unfamiliar cultural climate. The aid provides products including profiles of people relevant to psychological operations and cases of cultural interactions. The system consists of a model for the effects of culture on decision making and behavior, based on the Cultural Lens model of cultural differences in military domains, as well as a case-based reasoning engine that uses historical examples of scenarios and groups with specific cultural traits. We describe our current efforts focusing on articulation of a case base as well as the representations and artificial intelligence methods necessary to define and apply cultural aspects of behavior and decision-making. We also discuss the problem of cultural modeling in general, and the power and limitations of computational representations.