Kentucky Court Finds Execution of Offenders Aged 18-20 Unconstitutional

On 1 August 2017, a Kentucky court issued the first judicial ruling in the United States finding that the execution of offenders under the age of twenty-one amounted to cruel and unusual punishment in violation of the Eighth Amendment to the US Constitution. The court relied heavily on the opinions of experts regarding adolescent brain development in finding that eighteen- to twenty-one-year-olds are “categorically less culpable” than adults:

(1) they lack maturity to control their impulses and fully consider both the risks and rewards of an action, making them unlikely to be deterred by knowledge of likelihood and severity of punishment; (2) they are susceptible to peer pressure and emotional influence, which exacerbates their existing immaturity when in groups or under stressful conditions; and (3) their character is not yet well formed due to the neuroplasticity of the young brain, meaning that they have a much better chance at rehabilitation than do adults.

Kentucky v. Bredhold, Order Declaring Kentucky’s Death Penalty Statute as Unconstitutional, No. 14-CR-161, slip op. at 11 (Aug. 1, 2017).

One of the experts cited by the court was Laurence Steinberg, an expert in adolescent development whose research was cited by the US Supreme Court in Roper v. Simmons (where the Court found the execution of those under the age of 18 was cruel and unusual punishment).  Steinberg testified that “adolescents,” defined as individuals under the age of twenty-one, lack the capacity of adults to control their impulses, understand and assess risk, regulate their behavior and control their emotions.  Similar to child offenders, they also possess an increased capacity for change, making them particularly good candidates for rehabilitative programs.

The Kentucky court’s ruling embraced arguments that have recently been raised by anti-death penalty advocates in the United States, who in turn have relied on scientific studies demonstrating that the brain does not fully develop until the early twenties, and that the prefrontal cortex—which controls executive functions such as planning, impulse control, and reasoning—is the last to develop. In a 2009 amicus curiae brief submitted in the US Supreme Court case of Graham v. Florida, the American Psychological Association observed that while “[s]cience cannot, of course, draw bright lines precisely demarcating the boundaries between childhood, adolescence and adulthood,” the “qualities that distinguish juveniles from adults do not disappear when an individual turns 18.”

The Kentucky court acknowledged that the “study of brain development conducted in the past ten (10) years has shown that these key brain systems and structures actually continue to mature well into the mid-twenties (20s).” Indeed, several studies have concluded that the brain continues to develop—especially in young men—until the age of about twenty-five. In light of this, shouldn’t courts bar the execution of young offenders up to the age of twenty-five?

Critics of this proposal might argue that age can be taken into account as a mitigating factor at sentencing.  But this presupposes that judges and juries are capable of fairly weighing the scientific evidence demonstrating that young adults, like juveniles, lack the cognitive capacity of older adults. The US Supreme Court considered and rejected this argument in Roper: “An unacceptable likelihood exists that the brutality or cold-blooded nature of any particular crime would overpower mitigating arguments based on youth as a matter of course, even where the juvenile offender’s objective immaturity, vulnerability, and lack of true depravity should require a sentence less severe than death.”

On an international level, every human rights treaty to set an age cut-off for youthful offenders provides that only those under eighteen are categorically exempt from capital punishment.  During the drafting of the International Covenant on Civil and Political Rights (ICCPR) and the Convention on the Rights of the Child, there was little debate as to why eighteen marked the dividing line between child and adult.  In Roper, the US Supreme Court noted merely that “[t]he age of 18 is the point where society draws the line for many purposes between childhood and adulthood.”

Notwithstanding the multiple definitions of “child” as anyone under the age of eighteen, some nations already recognize that for the purposes of capital sentencing, the line should be drawn differently.  Zimbabwe’s 2013 Constitution prohibits the execution of offenders who were under the age of twenty-one at the time the offense was committed, and Cuba prohibits the execution of those who committed crimes while they were under twenty years old.  And in Malawi, courts have accepted that crimes committed by offenders aged 19-25 “may be a result of impetuous, immaturity, youth or adventure.” Republic v. Keke, Confirmation Case No 404 (HC) (2010) (unreported).

It is likely the Kentucky court’s ruling will be overturned on appeal.  But the opinion represents the first recognition by a judicial body that drawing the line at eighteen makes no sense in light of the new research on brain development and its effects on adolescent behavior.  It is time for the international community to take note of this evidence as well.  At a minimum, a powerful argument could be made that the execution of young adults under the age of 25 would be impermissibly arbitrary in violation of Article 6 of the ICCPR.