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America puts more people in jail and prison than any other country in the world. Although the country has managed to slightly reduce its prison population in recent years, mass incarceration remains a fact of the US criminal justice system.

It’s time for a radical idea that could really begin to reverse mass incarceration: capping all prison sentences at no more than 20 years. It may sound like an extreme, even dangerous, proposal, but there’s good reason to believe it would help reduce the prison population without making America any less safe.

In the 1980s and ’90s, American officials by and large believed the country was in the middle of a crime wave and an underincarceration crisis; they responded by increasing the length of prison sentences, enacting new mandatory minimums, and restricting the use of parole. Today, with crime rates lower, Americans more readily believe that the country has an overincarceration problem — one that disproportionately afflicts minority communities, as black and brown people are far more likely to be locked up than their white peers.

Given the impact that mass incarceration has had, there’s a strong case that the US should take steps to ensure that it doesn’t ever lock up so many people again.

Looking at the length of our prison sentences is one approach to reverse mass incarceration. Empirical research has consistently found that locking up people for very long periods of time does little to nothing to combat crime, and may actually lead to more crime as people spend more time in prison — missing big life opportunities for legitimate careers, and being incarcerated with others who have ties to the criminal world.

There’s also good reason to believe that 20 years is a good cutoff for a maximum. Studies have found that people almost always age out of crime, particularly by their late 30s and 40s. If a person is locked up for a robbery or murder at 21, there’s a very good chance that he won’t commit that same crime when he gets out at 41.

Other countries show this can work. European nations tend to have shorter prison sentences than the US, and certainly fewer people in prison, along with roughly equal or lower violent crime rates. Norway in particular caps the great majority of prison sentences at 21 years — and its violent crime and reoffending rates are lower than the US’s. (The cap does have some exceptions, as I’ll explain later.)

A cap on prison sentences wouldn’t on its own end mass incarceration. But at least tens of thousands of people in prison would benefit now — if the change were applied retroactively — and untold numbers more would benefit in the future if it were adopted by states and the federal government.

I’m not naive; I know there’s a very, very low chance that this policy will actually be enacted. And I know there are some difficult questions we need to confront if such a policy were ever put in place.

But I think pushing for something like this is a good idea anyway. It forces a conversation about what prisons are for: Are they for keeping the public safe? Rehabilitating inmates? Purely for revenge? If our answer as a society is the first two, but not the latter, then a cap is something we should consider.

By beginning these kinds of conversations, we can try to get at the root cultural and social forces that enabled and encouraged mass incarceration to begin with. Only by doing that can we start to really unravel a criminal justice system that’s turned into one of the world’s most punitive.

How a 20-year sentence cap could work

Capping prison sentences at 20 years — an idea that I first heard from Sentencing Project executive director Marc Mauer — is a really consequential policy change that could affect the lives of up to hundreds of thousands of people.

America’s prison population has exploded, from 330,000 in 1980 to 1.5 million in 2016 (though the figures have started to turn since 2009). That includes at least tens of thousands of people who are likely to spend decades in prison.

In The Meaning of Life: The Case for Abolishing Life Sentences, Mauer and Ashley Nellis wrote that the number of people sentenced to prison for life grew from 34,000 in 1984 to nearly 162,000 in 2016. The US is a huge outlier, Mauer and Nellis explained: “A comprehensive 2016 international analysis of life imprisonment found that the number of people serving life imprisonment in the United States is higher than the combined total in the other 113 countries surveyed.”

The idea for a cap is straightforward: No one could be sentenced for any number of charges — not attempted robbery, rape, or murder — for more than 20 years. There should be a limited exception, like there is in Norway, that lets courts extend prison sentences indefinitely for an additional five years at a time, but only if there’s proof that a person still poses a public safety threat.

For a lot of people, this is going to sound ridiculous. Twenty years for murder or rape? That doesn’t seem proportional to the crime.

But this gets us to a deeper conversation about the criminal justice system’s purpose. Is it for punishment? Is it for public safety? Is it for rehabilitation? Is it for all of the above, or something else entirely?

My guess is for those who believe prison should punish offenders, a cap is going to be really hard to swallow. The great, great majority of people who would benefit from this change are violent criminals who have absolutely done bad things. There’s no denying that. Americans may want those people to suffer.

But I think those views need to be reconsidered. Even without a cap, the majority of people in prison will be released and reenter society at some point. When we have those people literally captive, why not take the opportunity to try to make sure they can be productive members of society when they return? Why waste the potential of any human life if we have a chance, small or large, to turn it around?

And 20 years in prison is still a very long time, so people sentenced at the cap would still suffer. Mauer told me he tries to get people to think about what it’d be like to serve such a long sentence.

“Think back where you were in life 10 years ago,” he said. “What’s happened to you? What experiences have you had in 10 years? You might have gotten married or divorced. You might have had children. You might have had different jobs. You might have had health problems. Think through all the things that go through your life, and that’s a small window into what incarceration does.”

To me, that seems like a terrible punishment — even if I think it’s deserved.

Why this can work without hurting public safety: people age out of crime

What about the public safety case against capping prison sentences? Won’t a released murderer, rapist, or robber just go on to victimize more people?

This concern, while genuine, misunderstands people’s propensity to commit crime throughout their lives. Most murderers aren’t serial killers, and they aren’t very likely, especially decades later, to kill again. The same goes for other crimes.

The evidence is what’s known as the age-crime curve. It shows that people tend to age out of crime. In their mid- to late teens and early 20s, people are much, much likelier to commit a crime than they are in their 30s and especially 40s and on.

Here’s the age-crime curve for robbery in 2014, taken from Mauer and Nellis’s book:

As the chart makes clear, a person’s propensity to commit a crime — in this case, a robbery — is at its highest around 20 years old. But it drops quickly after that. In his 30s, a person’s chances of committing a robbery drop to 25 percent of what they were at 20. In his 40s, the chances drop to less than 12.5 percent. In his 60s, the risk nearly vanishes.

There are exceptions, like lifelong serial killers. But they’re few and far between, and could be handled with limited exceptions to a 20-year cap.

Virtually no one in criminology disputes the age-crime curve. Nancy La Vigne, vice president of justice policy at the Urban Institute, told me that it’s “pretty well established in the literature.”

This shouldn’t come as a surprise to most people, particularly those already in their 30s, 40s, or above. Think about how likely you were as a teen to break the law, with underage drinking, using illegal drugs, shoplifting, getting into fights, and so on. Now think about how likely you are to do that today, assuming you’re older. Regardless of whether you got caught in your teen years, you are likely an embodiment of the age-crime curve.

John Pfaff, a criminal justice expert at Fordham University and the author of Locked In: The True Causes of Mass Incarceration and How to Achieve Real Reform, told me there are a few reasons for the age-crime curve.

“Some of it is physical and hormonal: Testosterone levels go up, testosterone levels go down; violence goes up, violence goes down. Some of it is purely physical: Even if I was as aggressive now as I was 20 years ago, I’m 44 — things are slow, things ache a bit more,” he explained. “But some of it is also social: Getting married is a pathway out of crime; finding a career is a pathway out of crime. So the longer we keep people in prison, the longer we tend to undermine the ways these people mature and age out of crime as they get older.”

Other evidence backs this up. In 2017, David Roodman of the Open Philanthropy Project conducted an extensive review of the research on longer prison sentences. He concluded that “tougher sentences hardly deter crime, and that while imprisoning people temporarily stops them from committing crime outside prison walls, it also tends to increase their criminality after release. As a result, ‘tough-on-crime’ initiatives can reduce crime in the short run but cause offsetting harm in the long run.”

There’s also evidence that America’s mass incarceration experiment has not done much to make the US safer. A 2015 research review by the Brennan Center for Justice estimated that more incarceration — and its abilities to incapacitate or deter criminals — explained about zero to 7 percent of the crime drop since the 1990s, although other researchers estimate it drove 10 to 25 percent of the crime drop since the ’90s.

Meanwhile, prisons cost the US a tremendous amount. There’s the actual financial cost of putting people in prison, which the Prison Policy Initiative estimated at $182 billion in 2017. There’s also the social cost of people being ripped away from their families and communities; as one example, the New York Times calculated in 2015 that for every 100 black women not in jail or prison, there are only 83 black men — what amounts to 1.5 million “missing” men, who can’t be there for their kids, family, or community while incarcerated.

This would lower sentences for violent offenses. That’s good.

In the US, for a 20-year cap to really have an impact, the policy would have to be adopted by the states. Some 87 percent of prisoners in the US are held in state facilities. The change could also be enacted at the federal level, of course, and the feds could try to encourage states to implement such a change with financial incentives (although similar efforts in the past haven’t been very successful).

But the majority of those in state prisons are people convicted of violent offenses: In 2015, 54.5 percent of people in state prisons were in for violent crimes. About 15.2 percent were in for drugs.

Until now, much of the criminal justice reform movement has focused on reducing prison sentences for low-level, nonviolent offenders. A 20-year sentencing cap, however, would almost entirely benefit higher-level, violent offenders — which would be a good thing.

These violent offenders are not all, or even close to mostly, serial killers. They can be people who committed armed robberies but didn’t seriously hurt anyone. They can be accomplices of such crimes who never directly hurt anyone at all, such as the getaway driver in a robbery. They can be women who killed their abusers. They can be people who got into fights with friends or family under the influence of alcohol and other drugs but otherwise may not be likely to commit any violent crimes at all.

And violent offenders, overall, make up the majority of the state prison population.

This is why criminal justice activists and scholars, including Pfaff in Locked In, argue that America will have to at some point confront how it treats violent offenders if it really wants to undo mass incarceration.

As it stands, America’s incarceration rate is 655 per 100,000, which is higher than that of authoritarian nations like Cuba (510), Russia (389), and China (118). Democratic, developed nations tend to have even lower incarceration rates than the US; Canada’s is 114, Germany’s is 76, and Japan’s is 41.

When it comes to life imprisonment in particular, Mauer and Nellis’s book pointed to research that suggested the US accounts for 40 percent of the world’s total life sentences.

Because the US has higher lethal crime rates (largely due to easy access to guns) than other developed nations, there’s a good chance that the US will never have incarceration rates as low as other wealthy nations. Still, if the US wants to get back to its own historical trends — like in 1980, when the number of people in prison was around a fifth of what it is now — it has a lot of room for improvement. But to get that low, at least some violent offenders will have to be let out of prison sooner rather than later.

A cap will force us to think of prison as a place for rehabilitation

A big mental shift we need to make when thinking about prisons is to see them as something more than just for punishment or a public safety mechanism. We need to start entertaining the notion that prison can — should — be a place where we can rehabilitate the incarcerated.

Even today in US prisons, the majority of inmates will be released at some point. This is a fact we do a terrible job recognizing. The US notoriously underfunds rehabilitation and reentry services, contributing to rearrest rates of more than two-thirds within three years of release and more than three-quarters within five years. (Not all those arrests lead to reincarceration, since they can be for minor infractions.)

But if the US capped all prison sentences at 20 years, it would be forced to recognize a new reality: Just about everyone put in prison will, at one point, be free. And those people will very often need programs to ensure that they can transition back to a normal life.

This has long been the reality for Norway, even before it capped most prison sentences at 21 years (with a higher cap for terrorism and genocide). “There’s no tradition in Norway for keeping people in prison for life,” Ragnar Kristoffersen, a researcher at the University College of Norwegian Correctional Service who previously worked for the Ministry of Justice, told me.

As a result, Norway has built a prison system that looks very kind by US prison standards. (If you want to dive deep into this, I recommend reading Jessica Benko’s piece in the New York Times Magazine.) Cells are relatively comfortable. Rehabilitation programs are widely available; in fact, inmates are required to have at least one activity in the daytime, whether a job, education, or, say, a sex offender program. Guards are trained, with at least a two-year college requirement, to treat inmates with respect and facilitate their rehabilitation.

Norway also has better support once people get out of prison, with a stronger social safety net than the US — one that includes guarantees for health care and education. “People have something to go to,” Kristoffersen argued.

For Norway, this gets to a deeper cultural resistance to using prisons purely for punishment. “What’s the reason? Why do you sentence people? Why do you punish people? If it’s for revenge, then when is revenge enough?” Berit Johnsen, another researcher at the University College of Norwegian Correctional Service, told me.

That’s not to say that Norway’s prisons are a great place to be. Kristoffersen and Johnsen emphasized that, despite many media reports suggesting otherwise, being in Norway’s prisons is still unpleasant. Inmates still lose almost all their freedoms. They’re still taken from their friends, family, and communities. As Johnsen put it, “It is prison. You don’t want to go there.”

It’s not clear how much more effective Norway’s system is compared to the US’s. As Benko noted in the New York Times, the US reincarceration rate — which measures how likely released inmates are to be locked up again — over two years is about 29 percent. That’s only a bit higher than Norway’s rate of 25 percent. But Norway is still doing better, and its violent crime and homicide rates are much better too — suggesting that the cap, at the very least, doesn’t cause more crime even as it limits the harms of incarceration.

This is far from the only solution to mass incarceration, but it’s a good model to aim for

If America were to implement a 20-year cap on prison sentences, it would not end mass incarceration. If applied retroactively, it would likely lead to an earlier release for maybe a few hundred thousand inmates, at most, out of the 2.1 million people in jail or prison today.

The cap wouldn’t address the sentences for the majority of those 2.1 million people, who are in jail or prison for fewer than 20 years for anything from shoplifting to violent crimes.

A cap also, crucially, wouldn’t address jail and prison admissions. While America’s incarceration rate has increased over the years in part because people are spending more time in prison, it’s also the case that more people are being admitted to jail and prison in general. To tackle that problem, other changes would be needed, such as eliminating some crimes entirely so they don’t result in prison time (by, say, decriminalizing drug possession) or raising the bar for what kind of crime qualifies for prison time (like increasing the dollar amount for how much people must steal before they are sent to prison).

Setting a cap also wouldn’t address other problems in the justice system, from the death penalty to the stigmatization that follows a criminal record to poor conditions in prisons generally. The death penalty in particular may pose serious problems for the cap, since a cap may perversely incentivize courts and juries to send more people to death row if life imprisonment is no longer an option. So the death penalty would need to be repealed if a cap were instituted.

Even with an exception in place to extend prison sentences beyond the 20-year cap, there is a chance, however small, that sometimes courts will misjudge, and a person will be released when he shouldn’t have been. But this is also an issue for the current parole system, yet we accept the risk because we think it makes the system more proportional and just. If mass incarceration is a plight we want to get rid of, and that requires releasing some prisoners, we just have to take some of these risks. No solution is flawless.

So I think the cap is a good model to aim for — a daring idea that can really reset how we, as a society, think about prison. It leads to more systemic questions: If a prison sentence for murder is now a maximum of 20 years, can we really justify sending someone to prison for burglary or drugs for 10 or even five years? If someone is going to be released from prison eventually, shouldn’t we ensure that person has support both in and out of prison so he can transition back to society safely? If prison isn’t the end-all, be-all for stopping crime, should we not take other approaches more seriously?

I don’t write any of this lightly. I know there are some uncomfortable questions involved: Do we really want a just-released murderer living next door and working in the same office with us? Why should we give any sort of break to someone who commits horrific acts? Does a person who robbed someone else of any chances really deserve a second chance? All of this is going to be especially hard to confront for victims of crime, who have seen the harms inflicted by the kind of person who would benefit from this policy firsthand.

These are moral, abstract questions that I can’t provide a definitive answer to. But based on the evidence and statistics, these are hurdles that we, as a society, have to think about and overcome if we want to rid ourselves of mass incarceration. The reform advocates I spoke to said that a 20-year cap is a promising way to do that — although some of them were very emphatic that some sort of exception allowing longer sentences is necessary. (Along these lines, some reformers favor a “second look” provision that, instead of imposing a cap on sentences, merely requires a sentence reevaluation every 15 or 20 years.)

Now, is any of this politically feasible? Today, probably not. A Vox/Morning Consult survey from 2016, for one, found very little support for reducing punishments for violent offenders, even if they have a low chance of reoffending.

But in an era when views toward the criminal justice system are shifting, and discussions about everything from adopting a single-payer health care system to free college are growing, a 20-year cap on prison sentences seems like something more progressives could and should embrace.

If nothing else, the evidence strongly indicates that locking people up for longer isn’t doing much, if anything, to keep America safer. It’s time to try something new.

Watch: How Norway designed a more humane prison

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