Should 18-year-olds be imprisoned for life?

In the criminal justice system,18 is the traditional demarcation between juveniles and adults. But that line might be moving up, at least if advocates in a high-profile Supreme Judicial Court case have their way. Northeastern law professor and GBH legal analyst Daniel Medwed joined GBH’s Morning Edition co-host Jeremy Siegel to talk about this case and the issue of age and criminal responsibility. This transcript has been lightly edited.

Jeremy Siegel: Last week, the SJC heard an important case about whether people under the age of 20 may be given sentences of life in prison without the possibility of parole, or LWOP. Before we talk about this case, tell us about the backdrop here. What is the law about, who is and who is not eligible for LWOP sentences?

Daniel Medwed: Many states impose prison terms of life without the possibility of parole for juveniles under the age of 18, based on the idea that certain teenagers are incorrigible and their crimes are so egregious that they deserve to be locked away for the rest of their lives without even the theoretical chance for release. That's the theory. Starting in 2005, however, the Supreme Court gradually began to whittle away against that principle. The notion was that it violates the Eighth Amendment prohibition on cruel and unusual punishment to impose such a draconian sanction on people whose brains aren't fully developed. So in 2005, the Supreme Court banned the application of the death penalty to juveniles. Five years later, it banned LWOP sentences to juveniles convicted of non-homicide crimes.

And two years after that, in 2012, it said that LWOP sentences for juveniles convicted of homicide — that's also questionable. The following year, in 2013, the SJC acted and it banned the imposition of LWOP sentences for juveniles under the age of 18 in the commonwealth. So one lingering question, Jeremy, for the last 10 years or so is, is the age of 18 too arbitrary? Should that ban on LWOP sentences be extended to so-called late adolescence, people who are 18, 19 and 20?

Siegel: So there's this SJC case that could be pretty significant for this field. What are the facts involved in this case?

Medwed: There actually are a pair of cases. One of them involves a defendant named Sheldon Mattis, who in 2011, at the age of 18, was involved in the murder of another teenager in Boston. Mattis was convicted of first degree murder and given an LWOP sentence. But get this: His codefendant, who was 10 days shy of turning 18 and was actually determined to be the one who fired the fatal shot, he actually only got life with the possibility of parole, simply because he was a juvenile. The other case involves another man named James Robinson, who at the age of 18 was involved in an armed robbery that went awry and led to the death of a man in Brighton. Robinson also got LWOP.

So advocates for both Robinson and Mattis are arguing that this ban on LWOP sentences should be extended to people who are 18, 19 and 20. And if they are successful, Jeremy, it could affect about 200, I believe, 203 prisoners in Massachusetts.

Siegel: So, Daniel, is the idea that depriving late-adolescence people between 18 and 20 of a chance for parole also violates the Eighth Amendment, the one that involves cruel and unusual punishments? Would this be cruel and increasingly unusual for people that age?

Medwed: Yes, that's the main argument. The idea is that we now know from our study of adolescent brain science that the part of the brain, the prefrontal cortex, that governs cost-benefit analysis and impulse control, isn't fully developed in people until their 20s. And the idea of imposing full criminal responsibility on people whose brains aren't fully developed strikes many people as cruel and unusual. Another argument in favor of extending this ban is grounded in the racial disparities surrounding the imposition of LWOP sentences. According to some data in one of the briefs filed in this case, Black people are 16 times more likely to get LWOP sentences than white people.

Siegel: Daniel, what are the arguments against moving in this direction, allowing judges to continue to impose these sentences?

Medwed: One is based on a theory that legal scholars call institutional competence, that it's not up to the courts to make this determination, it should be the people. It should be our democratically elected representatives who decide where that line should be, 18, 19, or 20. Another argument is based on punishment theory. We treat 18-, 19- and 20-year-olds as adults for many purposes. They can get married, they can go to war, they can vote. Why not also treat them that way for purposes of criminal law? So it will be interesting to see how it plays out.