The discussion suggests that crime is a focal point for the human need to hold positive and negative attitudes toward social objects. This phenomenon of moral polarization can be explained on two levels. One is the level of historical development, as indicated by the religious, political, and humanitarian doctrines that underlie current moral judgments about crime in the United States. The other level is revealed in research literature in the behavioral and social sciences. Thus, psychologists have discerned a phenomenon that they call "psychological polarization"; sociologists, "social polarization"; and political scientists, "political polarization." These concepts seem to have developed independently, but they aid understanding of perceptions of crime. Although extremes of moral judgment are barriers to effective social action, a rational evaluation of harm as "bad" is an appropriate element of criminal justice policy. Index and over 400 references (Author summary modified)