The authors develop Bittner’s (1974) theory of the police by extending the analysis to a consideration of the effect of police encounters with the public over time. The main argument is that the expectation held by the public that the police will intervene whenever called has created an overarching and shared “idea of police,” which has become important to the preservation of law and order in democratic societies and is intertwined with police credibility. Indeed, it is suggested that the preservation of this “idea of police” is the main concern guiding police policy and management. The authors analyze the Kansas City Prevention and Newark Foot Patrol Experiments as well as the 1997 police strike in Brazil in terms of how the “idea of police” accounts for their outcomes. The patrol experiments highlighted the “idea of police” expectation of a real-time cause-effect relationship between police patrol and crime. Although actual crime rates were unaffected, citizens in the study areas felt safer and more satisfied with police when there were active patrols, the observation of which bolstered the “idea of police.” The “quasi-experimental” police strikes in Brazil and the ensuing chaos highlighted the strength, frailty, and explanatory power of the “idea of police.” The authors note that the “idea of police” explains why the issues of police strikes, police corruption, and police misuse of force occupy central positions in the public discourse and often cause emotional public outcry. The importance of police credibility is thus an important component of police policy and practice because it ensures the preservation of the “idea of police,” which is ultimately a “great economizer of police resources.” References, sources