It’s a bit startling how suddenly mass incarceration has come to seem like a really bad idea. There have been stubborn opponents all along, of course—and no doubt the incarcerated themselves were always skeptics—but as America’s rate of incarceration doubled from the mid‑1970s into the mid-’80s, then doubled again from the mid-’80s into the mid-’90s, and then continued to rise until the United States out-incarcerated every other country to become by far the world’s most ambitious warden (until about one in every four prisoners anywhere were behind American bars), most of us just went about our business as though nothing strange was happening. Publications like this one might have covered the phenomenon, but no political leader was really campaigning against it. You might say, in the enduring coinage of the sociologist and senator Daniel Patrick Moynihan, that Americans were defining deviancy down.

Or so it seems, because now, from the far left to the far right and, most remarkably, around the political center, politicians are scrambling over one another to deplore mass incarceration (a development that should also cheer the beleaguered advocates of bipartisanship). One should be humble about declaring the end of an era. But historians of the future might do worse than to cite the moment in July when Bill Clinton, who worked as hard as any Democrat to blunt the Republicans’ edge on law and order, said he had erred in signing a bill mandating longer sentences. “The bad news is, we had a lot of people who were essentially locked up who were minor actors, for way too long,” he said.

That is bad, indeed. But is it really news? Why are political leaders awakening to this monstrous mistake only now? Maybe, in part, because crime rates began dropping more than 20 years ago, and remain relatively low by postwar standards. Maybe Americans are less afraid.

The deeper question, the one Ta-Nehisi Coates answers with his cover story in this issue, is how the idea of mass incarceration took such a firm hold in the first place. How did it so completely override Americans’ humanity? How did things reach the point that it could make moral sense, for example, to lock up a 16-year-old boy for the rest of his life, and ignore repeated recommendations from a parole board that he be freed? Decades of prison reform preceded the great lockup of the past 50 years. In an article on such efforts in these pages more than 100 years ago, in 1911, our writer observed that getting locked away in an unreformed prison “is like going to a hospital to be cured of one disease and catching a worse one there which devitalizes the victim for life.” This is a very old insight. Yet it is now somehow new again.

Coates demonstrates that white Americans’ fear of black Americans, and their impulse to control blacks, are integral to the rise of the carceral state. A result is that one of every four black men born since the late 1970s has spent time in prison, at profound cost to his family. For this, Coates holds Moynihan, in part, responsible. Though his landmark report in 1965 on the disintegration of the black family stressed the ruinous legacy of “three centuries of sometimes unimaginable mistreatment,” it had the effect, Coates shows, of further isolating African Americans as a dangerous race apart. “One does not build a safety net for a race of predators,” Coates writes. “One builds a cage.”

The troubles of black families that Moynihan hoped to ameliorate have been egregiously compounded by the policy—mass incarceration—that was in the end deployed to address them. Yet the sudden political consensus around rejecting mass incarceration does not yet extend to a meaningful approach to doing anything about it. How can we depopulate the prisons? Who will pay to help convicts rejoin society? If Americans do not face the dark history of this era, and do not act on a deeper understanding of it than their leaders have evinced so far, the next spike in crime—the next spike in fear—may doom the nation, and generations more “minor actors,” to a repetition of this cycle.

Coates has ideas for how to face this challenge. And we have reason to think that even Moynihan himself—original and protean as he was—would have approved.