A case in point: after the 1999 massacre at Columbine High School, a police presence, including surveillance cameras and metal detectors, was ratcheted up at schools around the country, particularly in urban areas with largely working-class black and Latino student bodies. It was all to “protect” the kids, of course. At Columbine itself, however, no metal detector was installed and no heavy police presence intruded. The reason was simple. At that school in the Colorado suburb of Littleton, the mostly well-heeled white families did not want their kids treated like potential felons, and they had the status and political power to get their way. But communities without such clout are less able to push back against the encroachments of police power.