At a time of earnest debate on the size and role of government, relatively little attention has been paid to the Hoover Dam of American social engineering: mass incarceration.

As crime rates increased in the 1960s and ’70s, the prototypical liberal response — the amelioration of the social conditions thought to generate crime — seemed ineffective and woolly headed. “Law and order” campaigns became the norm in both parties, accompanied by policies, including mandatory minimum sentences, aimed at incapacitating the criminal class. The number of people behind bars in America rose from 314,000 in 1979 to about 2 million in mid-2013.

Few objected because this approach was accompanied by a dramatic decline in crime rates, which fell by half in some categories. Not all this was because of increased incarceration — better policing techniques played a significant role — but public safety was clearly improved by separating convicted criminals from prospective victims for longer periods. As the crime problem became less urgent, the issue largely faded. In polls, few Americans rank crime as a top concern.

But the social side effects of get-tough policies are coming under increasing scrutiny. On the left, Ohio State law professor Michelle Alexander presses the case against a criminal justice system that sweeps up large numbers of young African Americans, sometimes for relatively minor drug offenses, places them in dangerous and dysfunctional institutions and then, upon release, denies them basic democratic rights. “Today,” she points out, “there are more African Americans under correctional control — in prison or jail, on probation or parole — than were enslaved in 1850.”

But serious criticisms of mass incarceration have emerged on the right as well, summarized in a recent essay by Eli Lehrer in National Affairs. Lehrer critiques a system that removes 2 million people from the workforce, produces high levels of recidivism and (relatedly) subjects prisoners to inhumane conditions. Prison order is often maintained by gangs, with the tacit approval of prison authorities. By one estimate, 20 percent of inmates are subjected to coerced sexual contact.

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Mass incarceration is America’s tragic success. It is effective and indiscriminate. It has increased safety, and it has deepened resentment.

Lehrer raises the appropriate policy question: Can rates of incarceration be rolled back without compromising safety? His essay makes a good case for “yes,” outlining an approach that “continues to use incarceration as an important policy tool, but that changes the frequency and length of prison stays and vastly improves the circumstances and conditions within prison walls.”

This would involve, Lehrer says, “shortening, but not eliminating, mandatory minimum sentences.” Penalties for routine probation or parole violations would be swift but limited — days behind bars, rather than months or years. (Research indicates that the certainty of punishment in these cases matters more than its severity.) New technologies such as rapid drug tests and GPS tracking make alternatives to incarceration more realistic for some categories of offenders. And Lehrer argues forcefully for maintaining the bright moral line between punishment and degradation. It makes little sense to abuse and embitter inmates when 600,000 are returning to communities each year. Better to provide prisoner reentry programs to ease the transition to civilian life.

There is another effective response to crime mentioned by Lehrer that I’ve seen firsthand. Just out of college I worked at Prison Fellowship Ministries, a religious organization serving prisoners, ex-prisoners and their families. Among inmates, faith can encourage the deliberate choice of a new set of values. It also motivates volunteers who refuse to treat human beings as the sum of their crimes. Any criminal justice reform interested in the repair of broken lives will seek the partnership of religious groups.

Americans have often viewed their criminal justice system in the same way they view their sanitation system — as a mechanism designed to make unpleasant realities disappear. So it is remarkable that criminal justice reform is beginning to show some political momentum. Bipartisan measures that reduce reliance on incarceration have passed in Ohio, North Carolina, Georgia and, of all places, Texas.

Crime is among those rare issues that, over time, have cooled as a culture-war conflict. And one of the main reasons is the emergence of an odd ideological coalition that favors reform. It includes liberals concerned about the racial implications of current policy; libertarians offended by vast, routine imprisonment; and evangelicals who have adopted the humanitarian cause of prisoners.

At the overlap of these groups is a very American conviction: order, yes. But not the assumption of hopeless division.

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