“Emerging Adults” Can No Longer Be Sentenced to Life Without Parole: The Impact of Commonwealth v. Mattis

by Stevie Leahy

“[M]aturity is a gradual endeavor, and while age eighteen is a milestone, society does not view it as the end of the metamorphosis toward adulthood.”

– Wendlandt, J., concurring.

Building upon 8th Amendment protections established a decade earlier in Commonwealth v. Diatchenko, the Massachusetts Supreme Judicial Court (“SJC”) made the Commonwealth the first state by court decision to categorically ban life without parole (“LWOP”) sentences for individuals eighteen through-twenty years old. Commonwealth v. Mattis, 493 Mass. 216, 221-22 (2024). This ban includes mandatory and discretionary LWOP sentences and stands in stark contrast to the parallel federal precedent and most other states. The Mattis decision labels this category of eighteen through twenty -year-olds as “emerging adults.” Prior to this landmark ruling, Massachusetts was in the minority of states that required LWOP for these emerging adults convicted of murder in the first degree. Id. at 234.

In the January 2024 decision, the SJC wrestled with the question of whether a bright line at 18 is the appropriate cut-off for the prohibition on an LWOP sentence. Id. at 224, n.16. Current neuroscience research supports that brain maturation continues through an individual’s mid-twenties, and oral argument was heavily focused on where to draw the line. The 4-3 split decision, authored by Chief Justice Kimberly Budd, relied on Massachusetts precedent and “contemporary standards of decency” when it comes to the punishment and rehabilitation of those who commit crimes prior to the age of twenty-one. The decision also relied heavily on an updated scientific record, which was extensive. See, e.g., id. at 218 n.3, 219, n.8.

The Origin Story: Two Co-Defendants Convicted, Two Drastically Different Sentences

The underlying case centered on defendants Sheldon Mattis and Nysani Watt. At the time of the crime, Mattis was 18 and 8 months and Watt was 17. They were jointly tried and convicted of murder in the first degree on the theories of deliberate premedication and extreme atrocity or cruelty. Watt, the individual who fired the weapon and killed the victim, received a life sentence with the possibility of parole after fifteen years. Id. at 218. Mattis was sentenced to mandatory LWOP. Id. On appeal, the SJC remanded Mattis’s case for development of the record specifically as it pertained to brain development after the age of 17. Id. at 219.

In line with the most recent United States Supreme Court decision on under-18 LWOP sentencing, Jones v. Mississippi, the Commonwealth argued that such a sentence would be constitutional when imposed after an individualized hearing (often referred to as a Miller hearing based on earlier Supreme Court precedent). The SJC rejected this argument for discretionary LWOP for eighteen through twenty year olds.

After an extensive discussion of the federal framework, Chief Justice Budd’s decision relied on Superior Court Judge Ullmann’s four “core” findings of fact regarding emerging adults:

• they lack impulse control similar to sixteen- and seventeen-year-olds in emotionally arousing situations,
• they are more prone to risk-taking in pursuit of rewards than those under eighteen years and those over twenty-one years,
• they are more susceptible to peer influence than individuals over twenty-one years, and
• they have a greater capacity for change than older individuals due to the plasticity of their brains.

Id. at 225-29. Factors one, two, and four were found to be “well supported” by the extensive scientific record developed in the case. Factor three was found to be supported by experts, who all agreed that the most current research supports this conclusion. These factors provided the SJC “a scientifically informed view of emerging adults’ culpability” and supported the majority’s ruling that LWOP is unconstitutional when applied to emerging adults. Id. at 229.

The majority opinion referenced national and international movements to reinforce its decision. Chief Justice Budd looked to other states who are moving in the same direction when it comes to changing the bright line of eighteen years: California, Colorado, D.C., Illinois, Michigan, and Washington have all expanded protections for emerging adults, with age ranges extending to twenty-one and even up to age twenty-five in some circumstances. Id. at 232-34. Similarly, the United Kingdom has banned life without parole for any offender under twenty-one years of age at the time of the offense. The Supreme Court of Canada unanimously ruled that life without parole sentences were unconstitutional for all offenders, regardless of age.

Although research supports the idea that brain development continues through age twenty-five, when combined with contemporary standards of human decency, Justice Budd noted that there is no consensus within society to extend the prohibition that far. Id. at 235, n.30.

A Split Bench: Concurring and Dissenting Opinions

In the first concurring opinion, Justice Kafker agreed with the extension of the ban, writing to emphasize that “the letter and spirit of our trailblazing decision directs us to reach the same conclusion today that we reached a decade ago and extend those very same protections to the age group at issue—eighteen through twenty year olds.” Id. at 237. In that decision a decade ago, Diatchencko, the SJC categorically ruled that LWOP sentences were unconstitutional and did not defer to the Legislature. Again here, where the SJC is responding to a United States Supreme Court decision, the SJC should likewise not defer. Id. at 242.

In the second concurrence Justice Wendlandt, joined by Justice Gaziano, dug into the issue of whether the Legislature should have made this decision. In plain English, easily digestible for a non-attorney, Justice Wendlandt summarizes the outcome of extending the ban based on updated neuroscientific research: “a child does not go to bed on the eve of her eighteenth birthday and awaken characterized by a lessened ‘transient rashness, proclivity for risk, and inability to assess consequences.’” Id. 250. After a comprehensive review of statutes, the scientific record, the judges’ collective experiences, and “common sense,” Justice Wendlandt agreed with the extension of the LWOP ban up to age twenty-one as the constitutional duty of the SJC under Article 26 of the Massachusetts Declaration of Rights. Id.

In the first dissent, Justice Lowy, joined by Justices Cypher and Georges, wrote that great deference is owed to the Legislature’s right to define the punishment for criminal behavior and define the line between juvenile and adult offenders. He argued that contemporary standards of decency do not clearly reflect that LWOP would be cruel and unusual for emerging adults (under either the 8th Amendment or Article 26). Id. at 255. Because the Legislature has drawn the bright line at eighteen, that is the line the Commonwealth should use. Therefore, the majority opinion “impermissibly engages in legislative line drawing, detached from our constitutional analysis.” Id. at 270.

In the second dissent, Justice Cypher agreed with the principal arguments outlined in the first dissent, “namely, [that] it is the Legislature, not the judiciary, that prescribes punishment.” Id. at 281. Justice Cypher wrote separately for four reasons: (1) extension of the prohibition is the job of the Legislature; (2) the majority’s reliance on Diatchenko is mistaken; (3) drawing a judicial line at twenty is inherently capricious; and (4) arbitrary reliance on neuroscience raises troubling, if unintended, implications for other groups. Id. at 283-84. As to the third and fourth points, Justice Cypher raised critical questions for the future of LWOP in Massachusetts; as was discussed at oral argument, the research supports the argument that brain development continues up through age 25. Id. at 283. Will future judges “follow the science” (despite the perils described by Justice Cypher) and extend the prohibition further?

Future Implications of Mattis in the Commonwealth

The implications for this specific defendant, Mattis, are that the SJC has remanded his case to the Superior Court for resentencing consistent with the opinion. For other similarly-situated emerging adults, parole is not automatic—it will depend on when the individual was originally sentenced (pre- or post-2014). However, the majority decision means that all those emerging adults must be given at least an opportunity to obtain release by the Massachusetts parole board. This decision will impact approximately 200 individuals (200 men, three women) currently serving LWOP terms in Massachusetts prisons. These 200 people will be incentivized to make themselves appealing candidates for parole consideration.

The Mattis decision has already been cited in briefs outside of Massachusetts, and this is likely to be the first domino in a series of jurisdictions that follow in the footsteps of the SJC. Just as Justice Kafker referred to the earlier Massachusetts precedent in this area as “trailblazing,” this decision is likely to be seen in the same light.

Stefanie (Stevie) Leahy is a professor in the Suffolk University School of Law Legal Practice Skills program. Prior to joining Suffolk, Professor Leahy was an Assistant Professor at Northeastern University School of Law. Professor Leahy also served as the Resident Fellow for the Center for Public Interest Advocacy and Collaboration, working on issues related to juvenile sentencing and the cradle to prison pipeline.