Federal, state, and local governments use the criminal justice system to carry out policies intended to reduce gang crimes, such as imposing curfews on minors. Critics of such strategies maintain that police tend to show bias in their efforts to end gang violence—contending, for example, that police are more likely to arrest minority youth than white youth for curfew violations.

One criminal justice tool that has been tainted by possible police bias is the implementation of injunctions to regulate gang behavior. Injunctions target known and suspected gang members in specific neighborhoods and bar them from behaviors such as gathering in public and carrying pagers. Gang members who violate an injunction are arrested.

However, the future of injunctions in the Los Angeles neighborhoods of Pico-Union and MacArthur Park is questionable. In September 1999, an investigation in the Los Angeles...