It certainly had consequences. It energized a movement, as one state after another enacted laws making it possible to try children as young as 13 or 14 as adults. (New York had such a law even earlier, and it is now being applied to Kahton Anderson.) Many hundreds of juveniles were sent to prison for life, though in the last few years the United States Supreme Court has ruled that such sentences must not be automatic, even in murder cases. Individual circumstances and possible mitigating factors should be weighed, the justices said.

Inescapably, superpredator dread had a racial component. What the doomsayers focused on, in the main, were young male African-Americans. For Steven A. Drizin, a law professor at Northwestern University writing for The Huffington Post last September, the deep-seated fear that any black teenager in a hoodie must be up to no good was essentially what got Trayvon Martin killed in Florida two years ago.

But how to explain the decline in youth violence?

Various ideas have been advanced, like an improved economy in the late ‘90s (never mind that it later went south), better policing and the fading of a crack cocaine epidemic. A less conventional — not to mention amply disputed — theory was put forth by some social scientists who argued that the Supreme Court’s 1973 ruling on abortion in Roe v. Wade had an impact. With abortions more readily available, this theory went, unwanted children who could be prone to serious antisocial behavior were never born.

The superpredator scare fit neatly with a “lock ‘em up and throw away the key” approach to rising crime that had taken hold even before the ‘90s. Many states are now moving in the opposite direction, if only because incarceration is expensive, in both its human toll and its burden on strapped government budgets.

Still, closing prisons is fraught with political peril. Maximum-security prisons in New York State, for example, are typically located in more or less rural areas, and are filled with inmates from New York City. Downstate crime produces upstate jobs, for corrections officers and others. So, even in an era of declining crime, any attempt to reduce the state’s inventory of prison cells runs into resistance from upstate elected officials.

Fears about predators, super or not, have not entirely disappeared. Of late, some are concerned about what is called “the knockout game.” It involves a young man or group of young men punching a stranger on the street. This is cast essentially as a black-on-white crime, perhaps a gang initiation rite. No question, such assaults have taken place. But are they part of an organized “game”? In New York, the police seem unsure if they amount to more than isolated incidents.

As for superpredators, not everyone has abandoned the notion. In the ‘90s, Mr. DiIulio called those youngsters “remorseless” and “impulsive,” describing them as unburdened by “pangs of conscience.”

Hmm, said Richard Eskow. Or words to that effect. Mr. Eskow, a senior fellow with the Campaign for America’s Future, wrote for The Huffington Post two years ago that he knew a group of people who matched those very descriptions. They were, he said, the reckless bankers and Wall Street high rollers who almost brought the United States economy to its knees a few years ago.

CLYDE HABERMAN, a regular contributor to Retro Report, has been a reporter, columnist and editorial writer for The New York Times, where he spent nearly 13 years based in Tokyo, Rome and Jerusalem. Subscribe to our newsletter here and follow us on Twitter @RetroReport.

This article first appeared in The New York Times.