Due process and the prohibition against disproportionate punishment did not require trial court to instruct on irresistible impulse as the standard for sanity of a juvenile offender. Marsh, a juvenile offender, was found guilty of two counts of first degree murder. After often expressing a desire to kill, he randomly selected a home in the middle of the night and stabbed an elderly couple to death, mutilating their bodies. He was found sane following the sanity phase of the trial. On appeal, he argued that due process and the prohibition against disproportionate punishment required the trial court to instruct on irresistible impulse as the standard for sanity of a juvenile, based on the same body of research on the development of brain function in adolescents that led to the decisions in Miller v. Alabama (2012) 567 U.S. 460 and Roper v. Simmons (2005) 543 U.S. 551. Held: Affirmed on this point. Due process does not impose any particular definition of sanity on the states or require the use of irresistible impulse as a measure of sanity. (California abrogated the irresistible impulse test in 1982.) The focus of Miller and Roper was the recognition that juveniles are constitutionally different from adults for purposes of sentencing. Their diminished culpability and greater potential for reformation make them not as deserving of the most severe punishments, but that does not mean they are less deserving of any punishment. The constitutional protection against disproportionate punishment does not prohibit punishment for conduct in response to an irresistible impulse. The trial court properly instructed the jury at the sanity phase of the trial. [Editor’s Note: In an unpublished portion of the opinion, the Court of Appeal concluded that Prop. 57 applies to Marsh’s case. The court conditionally reversed the criminal court’s judgment and remanded the case to the juvenile court to hold a transfer hearing.]

The full opinion is available on the court’s website here: http://www.courts.ca.gov/opinions/documents/C078999.PDF