ABSTRAK
A program titled "Operation Valkyrie" and implemented by the Illinois State Police for the purpose of interdicting drugs is presented as a study that illustrates reciprocity between a police organization and its institutional milieu. Information regarding this program was obtained from interviews with state police officials, from defense counsel who represented plaintiffs in interdiction cases, and from court records of Valkyrie interdictions. It is suggested that two aspects of its institutional environment, the environment of legal precedent in which the program is embedded and the network of state and federal agencies using similar interdiction strategies, influence the organization and activity of Operation Valkyrie. The article argues that current program activity reveals the way in which Operation Valkyrie is, in turn, affecting these two aspects of its institutional environment.