Police are authorized only to enforce the law; their use of discretion in other areas is not authorized, but the elimination of discretion is neither possible nor desirable. Neither is the formal authorization of discretion an appropriate approach, because this would require the recording and evaluating of the use of discretion, a difficult and problematic process. An alternative to a formal authorization of police discretion is the exercise of authority derived from knowledge and experience pertinent to the resolution of a particular problem. Such authority, however, is possible only in a cooperative context where coercion cannot be used to enforce authority. This limitation on authority would not be acceptable for police. Another source of informal authority is community expectation, where the community holds certain expectations for police services. A lack of consensus of expectation, however, makes this authority problematic. What is required is an informal authority inherent in the police role rather than in individual officers and that can use coercion. These conditions are fulfilled when police perform peacekeeping and social service functions customarily assigned to other professionals (such as probation officers, social workers, parents, and medical personnel) who, in a given situation, are not present at a scene where their authority is required. The police thus assume the authority of a stand-in, which has neither the disadvantages of formal authority nor the disadvantages of informal authority without role definition or coercion capability. Fourteen readings are listed along with 10 notes.