“The reactive policing of the early 1990s was easy,” Lou Turco, president of the Lieutenants Benevolent Association in New York City, told me in an interview. “You waited for a complainant to tell you that they’ve been a robbery victim. The hard thing is to get someone off the corner before there’s a victim.” It is this proactive policing, when there is no complainant, that can get you in trouble now, Mr. Turco says. “Every cop today is thinking: ‘If this stop turns bad, I’m in the mix.’ ”

An officer in South Central Los Angeles described the views of his fellow cops: “Guys and gals in coffee shops are saying to each other: ‘If you get out of your car, you’re crazy, unless there’s a radio call.’ ”

One would think that cop critics would celebrate this drop in self-initiated police activity, which Radley Balko calls “dehumanizing.” They can’t have it both ways: Denouncing the police for proactively enforcing the law, then accusing them of a “dereliction of duty,” in Charles Blow’s words, when they quite understandably decrease such enforcement.

Many residents of high-crime areas don’t look at proactive and public-order enforcement the way their alleged advocates do. In a recent Quinnipiac poll of New York City voters, 61% of black respondents said they wanted the police to actively enforce quality-of-life laws in their neighborhood, compared with 59% of white voters.