New York Times

WASHINGTON — The Supreme Court on Monday agreed to hear two appeals raising questions about the roles race and intellectual disability might play in capital prosecutions.

One case, Buck v. Stephens, No. 15-8049, arose from a psychologist’s testimony that black defendants were more dangerous than white ones.

The case concerns Duane Buck, who was convicted of the 1995 murders of a former girlfriend and one of her friends while her young children watched. Texas law allows death sentences only if prosecutors can show the defendant poses a future danger to society.

During the trial’s sentencing phase, Mr. Buck’s lawyer presented testimony from the psychologist, Walter Quijano, who said that race was one of the factors associated with future dangerousness. “It’s a sad commentary that minorities, Hispanics and black people, are overrepresented in the criminal justice system,” Dr. Quijano testified.

A prosecutor followed up. “The race factor, black, increases the future dangerousness for various complicated reasons — is that correct?”

One of Mr. Buck’s trial lawyers, Jerry Guerinot, has a dismal record in death penalty cases, having represented 20 people sentenced to death in Texas, more than are awaiting execution in about half of the states that have the death penalty.

In their petition seeking Supreme Court review, Mr. Buck’s new lawyers said that his trial lawyers had been ineffective and that Mr. Buck’s death sentence was infected by racial bias.

“Left uncorrected, trial counsel’s injection of explicit racial discrimination into Mr. Buck’s capital sentencing profoundly undermines confidence in the integrity of both Mr. Buck’s death sentence and the criminal justice system over all,” Mr. Buck’s lawyers told the justices.

The cases will be argued during the court’s next term, which starts in October.

In turning down an earlier appeal from Mr. Buck in 2011 based on assertions of prosecutorial misconduct, five justices expressed misgivings about what had happened at his trial.

“Dr. Quijano’s testimony would provide a basis for reversal of petitioner’s sentence if the prosecution were responsible for presenting that testimony to the jury,” Justice Alito wrote. “But Dr. Quijano was a defense witness, and it was petitioner’s attorney, not the prosecutor, who first elicited Dr. Quijano’s view regarding the correlation between race and future dangerousness.”

Justice Sonia Sotomayor, joined by Justice Elena Kagan, said she would have voted to hear the case even as a challenge to prosecutorial misconduct. She noted that in 2000 the state’s attorney general, John Cornyn, had seemed to promise to allow new sentencings for several inmates, including Mr. Buck, who had been sent to death row based in part on Dr. Quijano’s testimony.

The justices also agreed on Monday to hear an appeal from Bobby J. Moore, who has been on death row since 1980 for fatally shooting a 72-year-old Houston supermarket clerk, James McCarble, during a robbery. That case, Moore v. Texas, No. 15-797, raises questions about whether Texas uses outdated standards in assessing whether a defendant’s intellectual disability was severe enough to bar his execution.

When the court ruled in 2002 in Atkins v. Virginia that the Constitution forbade the execution of people with mental disabilities, it gave states only general guidance. It said a finding of intellectual disability required proof of three things: “subaverage intellectual functioning,” meaning low I.Q. scores; a lack of fundamental social and practical skills; and the presence of both conditions before age 18. The court said I.Q. scores under “approximately 70” typically indicated disability.

In 2014, in Hall v. Florida, though, the court ruled that Florida’s I.Q. score cutoff was too rigid to decide which mentally disabled individuals must be spared the death penalty.

“Florida seeks to execute a man because he scored a 71 instead of 70 on an I.Q. test,” Justice Anthony M. Kennedy wrote for the majority in a 5-to-4 decision.

In Mr. Moore’s case, a trial court found that he was intellectually disabled and constitutionally ineligible for the death penalty. An appeals court reversed that decision, saying the lower court had erred by “employing the definition of intellectual disability presently used.”

The appeals court ruled that a 23-year-old standard applied instead and that, under it, Mr. Moore was not intellectually disabled.

When the Supreme Court announced on Monday morning that it would hear Mr. Moore’s case, it said the justices would also consider a second question: whether executing a condemned inmate more than 35 years after he was sentenced to death violates the Eighth Amendment’s prohibition against cruel and unusual punishment.

Some two hours later, the court issued a revised order, limiting its review to the intellectual-disability issue.

Two members of the court, Justices Kennedy and Breyer, have invited challenges to prolonged solitary confinement. “Years on end of near total isolation exact a terrible price,” Justice Kennedy wrote, for instance, in a concurrence last year, adding that “the condition in which prisoners are kept simply has not been a matter of sufficient public inquiry or interest.”

The court also agreed to hear an appeal in a gerrymandering challenge to Virginia’s legislative map, Bethune-Hill v. Virginia Board of Elections, No. 15-680. That case will also be argued in the next term.