The U.S. Supreme Court agreed Monday to take up two cases that could reshape how states handle jury composition and death-penalty claims, one involving a convicted killer's bid to use updated medical standards to avoid execution, and another challenging Florida's longstanding practice of seating six-person juries in non-capital criminal trials.
The justices will hear oral arguments in Guerrero v. Johnson and Kian v. Florida in the fall, with decisions expected in 2027. Both cases carry consequences well beyond the individual defendants. Together, they force the Court to draw fresh lines around two bedrock questions: what evidence a death-row inmate can invoke after sentencing, and whether the Sixth Amendment's guarantee of a jury trial means anything less than twelve citizens.
As The Center Square reported, the Court's decision to grant review arrives at a moment when capital punishment and criminal-procedure standards are already at the center of fierce national debate.
The first case, Guerrero v. Johnson, traces back to 2006, when Dexter Johnson was sentenced to death after being convicted for the kidnapping, rape, and murder of Maria Aparece. Johnson later sought to avoid execution by claiming intellectual disability, but the legal fight hinges not on his original trial record. It hinges on a book.
Johnson's lawyers pointed to diagnostic tools published in the DSM-5, the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, which came out in 2013, seven years after his conviction. They argued that because the criteria for assessing intellectual disability changed with the new manual, Johnson's claim now has "possible merit" even though it had none under the older standards.
Eric Guerrero, director of the Texas Department of Criminal Justice's Correctional Institutions Division, is the named respondent. Lawyers for Texas pushed back hard, telling the Court that the lower-court ruling gutted the limits on post-sentencing evidence.
"This holding erases the strict limits on claims based on new evidence. It had no possibility of merit without the new evidence."
That argument cuts to a principle conservatives have long defended: finality in criminal sentencing. If a convicted murderer can reopen his case every time a professional organization updates a diagnostic manual, the door swings wide for an endless cycle of post-conviction challenges. The victim, Maria Aparece, has no such luxury of revision.
The federal government has meanwhile moved aggressively to restore and strengthen capital punishment at the national level. The DOJ's recent push to expand the federal death penalty underscores the broader policy landscape in which this case will be decided.
The second case, Kian v. Florida, raises a different but equally fundamental question. Hamed Kian was convicted by a six-person jury of practicing as a chiropractor without a license and sentenced to more than a year in prison. He challenged Florida's law allowing juries of fewer than twelve people in non-capital cases.
Kian's lawyers reached all the way back to the Magna Carta to make their point. They argued that Supreme Court precedent dating to 1898 affirms that a jury means twelve people, and that this understanding has held since 1215.
"Since the time of Magna Carta, the word 'jury' has been understood to mean a body of twelve."
Their brief went further, citing the Court's own reasoning that the word "jury" in the Sixth Amendment was "placed in the constitution of the United States with reference to" the meaning it carried at common law, namely, a panel of twelve.
Florida's lawyers countered that the state's jury structure has served its citizens for over a century and a half, and that the Supreme Court itself has more recently affirmed the use of six-person panels in non-capital proceedings.
"For nearly as long as states have had a Sixth Amendment duty to provide criminal jury trials, this Court's message to the people of Florida has been clear: the jury structure that they have settled on for a century and a half fulfills that duty."
Florida is not alone. Connecticut, Indiana, Massachusetts, Utah, and Arizona also allow six-member juries in cases that do not involve the death penalty. A ruling against Florida's practice could force all six states to overhaul their trial systems.
These two cases may look like narrow procedural disputes. They are not. Guerrero v. Johnson will determine whether evolving medical literature can be used as a backdoor to reopen settled death sentences, a question with direct implications for how firmly the justice system can hold convicted killers accountable.
The case arrives as federal prosecutors have also been seeking the death penalty in major criminal prosecutions, signaling that the executive branch views capital punishment as a necessary tool against the worst offenders.
Kian v. Florida, meanwhile, forces the Court to decide whether the Sixth Amendment means what it said when it was written, or whether states can quietly whittle down one of its core guarantees. For originalists, the answer should be straightforward. The word "jury" had a specific, centuries-old meaning when the Founders adopted it. Shrinking that panel to six is not a minor procedural adjustment. It changes the math of deliberation, the burden of persuasion, and the protection afforded to every defendant who walks into a courtroom.
The composition of the Court itself adds another layer of significance. With speculation swirling around a possible Alito retirement and the conservative majority's future, the justices who hear these cases in the fall may be shaping criminal-law doctrine for a generation.
The Court has already been active this term on criminal-law questions. Just days ago, the justices delivered opinions touching on criminal venue rules as the current term winds down. The addition of Guerrero and Kian to next term's docket signals that the justices are far from finished with the hard questions about how the Constitution constrains, or permits, state criminal-justice practices.
Several details remain unclear. The scheduled oral argument dates have not been announced. The lower-court procedural histories in both cases, including which appellate courts issued the rulings now under review, were not specified in the Court's announcement. And the precise Florida statute governing six-person juries has not been publicly identified in connection with the grant of certiorari.
What is clear is that both cases pit longstanding state practices against constitutional text and precedent. Texas wants to keep the door shut on post-sentencing claims built on evidence that did not exist at trial. Florida wants to keep seating juries of six. The defendants want the Court to say the Constitution requires more.
For victims, taxpayers, and anyone who believes criminal law should mean what it says, the stakes are plain. A system that lets convicted murderers relitigate sentences every time a medical manual gets a new edition is not a system built for justice. And a jury that falls short of twelve is a jury that falls short of the Constitution's plain meaning.
The Court took these cases for a reason. The country will find out next year whether the justices still believe the words in the Constitution mean what they meant when they were written.