For people opposed to the death penalty in the United States, life without parole sentences (LWOP) have provided a kind of safe harbor. They offer an alternative to capital punishment that is severe enough to satisfy retributive demands and offer assurances that dangerous offenders will be incapacitated.

But, LWOP has proven to be a kind of attractive nuisance. It suffers from many of the same defects that have plagued, and continued to plague, death sentencing in the United States. At a time when great progress has been made in the effort to end the death penalty in the United States, it is time to think seriously about how to reform and ultimately end life without parole sentencing as well.

Last Thursday, the Massachusetts Supreme Court took an important, though limited, step in that direction when it said that is unconstitutional to use LWOP to punish people who committed their crimes when they are 18, 19, or 20 years old.

As a report on Boston public radio station WBUR explains:

The case involved Sheldon Mattis, who is serving a life sentence for his role in the 2011 fatal shooting of Jaivon Blake in Dorchester. Mattis was 18 at the time of the shooting. He had given a gun to Nyasani Watt, who shot Blake. Both defendants were convicted of first-degree murder, but because Watt was then under 18, he was deemed eligible for parole after 15 years. Watt was sentenced to life without the possibility of parole.

Before looking more closely at what the Massachusetts court did, let’s look at the history and use of LWOP and at some of its most serious problems.

Life without parole sentencing has been a feature of American penal practice for almost a century. Some of the earliest uses are found in habitual criminal statutes, now more popularly known as three-strikes laws. A century ago Ohio enacted an habitual criminal statute that said that those who were sentenced as habitual criminals would “serve a term of his or her natural life.”

Since the middle of the 20^th century, LWOP also has been used to punish murderers. Death penalty abolitionists played a crucial role in that development and believe they reaped great benefits from doing so.

As law professor James Liebman argues, LWOP “has been absolutely crucial to whatever progress has been made against the death penalty. The drop in death sentences… Would not have happened without the LWOP.”

It may be, however, that LWOP is less important in the struggle against the death penalty than Liebman and abolitionists assume. Research suggests that having LWOP on the books produces only “a small decrease in the number of death sentences handed down, but it has not led to a significant reduction in executions.”

Nonetheless, many states have expanded the reach of LWOP sentences to cover noncapital offenses.

Looking back to our country’s recent past reveals that in each decade of the last part of the 20^th century, at least eight states joined the list of those authorizing life without parole sentencing. Today it is fair to say, quoting New York Times reporter Adam Liptak, that the United States has “created something never before seen in its history and unheard of around the globe: a booming population of prisoners whose only way out of prison is likely to be inside a coffin.”

LWOP, like the death penalty, is a final and ultimate judgment. As such, it requires the same kind of arrogance and belief that humans can know what someone deserves, and will deserve, from the moment that they are sentenced to the moment that they die.

LWOP sentencing also suffers from practical defects like those also seen in the death penalty system. One of the most serious of those defects is the great racial disparity among people sentenced to life without parole.

In 2016, the Prison Policy Initiative found that 56% of those serving life without all sentences were Black and another 7% were Hispanic, while Blacks comprised only 13% of the American population and Hispanics 17%.

A study carried out in 2010 found that across the country Black youths were serving life without parole sentences “at a rate of about 10 times that of white youths.” In Massachusetts, research suggests that “Black people are serving [life without parole] for offenses at ages 18-20 at a rate more than sixteen times the rate for White people.”

Such problems explain why it’s time to reconsider the way this country uses LWOP sentences and whether it should use them at all. As we do so, people who want to end LWOP also need to think about what is the best strategy for mounting a campaign against it.

Here I think we can draw lessons from the campaign to end the death penalty. One of the most important of those lessons is the value of incremental steps.

This is why what the Massachusetts Supreme Court did is so important. It extended the constitutional prohibition of LWOP sentences in that state to people under 21 at the time they commit their offense.

In 2013, it had ruled that defendants under 18 could not be sentenced to life without parole because, as the court said, “it is not possible to demonstrate that a juvenile offender is ‘irretrievably depraved.’” LWOP, it held, is “cruel or unusual as imposed on a juvenile in any circumstance.”

In that case, it was following the lead of the United States Supreme Court which, one year earlier, “recognized the need to protect nearly all youth from life-without-parole sentences, regardless of the crime of conviction. Life without parole, as a mandatory minimum sentence for anyone under age 18 was found unconstitutional.”

In contrast, Thursday’s decision makes it the first court in the country to extend that holding to cover “emerging adults,” even those who, like Mattis, commit murder.

As they did in their 2013 ruling, last week the justices of the Massachusetts Supreme Court followed the science of brain development to reach the conclusion that people under 21 are biologically and morally more like their younger counterparts than they are like fully formed adults.

As Chief Justice Kimberly Budd explained in her majority opinion, “Advancements in scientific research have confirmed what many know well through experience: the brains of emerging adults are not fully mature. Specifically, the scientific record strongly supports the contention that emerging adults have the same core neurological characteristics as juveniles have.”

Or as Justice Dalila Wendlandt put it in her concurring opinion, those findings “confirm what any parent of an adult child can tell you: a child does not go to bed on the eve of her 18^th birthday and awaken characterized by a lessened ‘transient rashness, proclivity for risk, and inability to assess consequences.’”

Still neither Chief Justice Budd nor Justice Wendlandt wanted to leave any doubt about how they assessed the seriousness of the crime Mattis had committed. Budd, in particular, went out of her way to assure people who read her opinion that she did not intend to “diminish the severity of the crime of murder in the first degree, because it was committed by an emerging adult.”

Nonetheless, she held that for even the most serious crimes “emerging adults” should, because of “unique characteristics” that make them “constitutionally different” from adults, have a chance for redemption and an opportunity to be released from prison if. and when, they are rehabilitated.

Approximately 200 people could be eligible for parole because of Thursday’s ruling. But the implications of the decision for the future of LWOP go well beyond their fate.

The Massachusetts Supreme Court documented an emergent national consensus that such sentences are incompatible with evolving standards of decency. Budd noted, “22 states and the District of Columbia do not mandate life without parole in any circumstances. Of the remaining 28 states, only 12 (including Massachusetts) mandate life without parole.”

In the end, as Charles Ogletree and I wrote in 2012, “LWOP forces us to ask whether death is different-or at least whether a slow death sentence is much different than us with one…. Seen in this light, LWOP may well be the new capital punishment, with all its baggage-but none of its process.”

For those troubled by the state’s use of ultimate punishments, ending LWOP should be next on the agenda.