Public opinion polls suggest that American's trust in the police and courts is declining. The same polls also reveal a disturbing racial divide, with minorities expressing greater levels of distrust than whites. Practices such as racial profiling, zero-tolerance and three-strikes laws, the use of excessive force, and harsh punishments for minor drug crimes all contribute to perceptions of injustice. In Trust in the Law, psychologists Tom R. Tyler and Yuen J. Huo present a compelling argument that effective law enforcement requires the active engagement and participation of the communities it serves, and argue for a cooperative approach to law enforcement that appeals to people's sense of fair play, even if the outcomes are not always those with which they agree.

Based on a wide-ranging survey of citizens who had recent contact with the police or courts in Oakland and Los Angeles, Trust in the Law examines the sources of people's favorable and unfavorable reactions to their encounters with legal authorities. Tyler and Huo address the issue from a variety of angles: the psychology of decision acceptance, the importance of individual personal experiences, and the role of ethnic group identification. They find that people react primarily to whether or not they are treated with dignity and respect, and the degree to which they feel they have been treated fairly helps to shape their acceptance of the legal process. Their findings show significantly less willingness on the part of minority group members who feel they have been treated unfairly to trust the motives to subsequent legal decisions of law enforcement authorities.

Since most people in the study generalize from their personal experiences with individual police officers and judges, Tyler and Huo suggest that gaining maximum cooperation and consent of the public depends upon fair and transparent decision-making and treatment on the part of law enforcement officers. Tyler and Huo conclude that the best way to encourage compliance with the law is for legal authorities to implement programs that foster a sense of personal involvement and responsibility. For example, community policing programs, in which the local population is actively engaged in monitoring its own neighborhood, have been shown to be an effective tool in improving police-community relationships.

Cooperation between legal authorities and community members is a much discussed but often elusive goal. Trust in the Law shows that legal authorities can behave in ways that encourage the voluntary acceptance of their directives, while also building trust and confidence in the overall legitimacy of the police and courts.