When blacks and Hispanics across the U.S. read recent headlines about the practice of "racial profiling" by state troopers in New Jersey, it didn't strike them as an obscure practice in a far-off state. It sounded like their own experience. They have long believed it's no coincidence that so many of them have been stopped and frisked by police for no apparent reason. African Americans even coined a term for their supposed offense: DWB, for Driving While Black.
Last week their suspicions gained supporting evidence. A 43-page report released by the American Civil Liberties Union showed the problem to be of...