PHOENIX — The US Supreme Court will hear an appeal Wednesday by an Arizona death row inmate who is seeking a new sentencing trial, arguing the horrific physical abuse that he suffered as a child wasn’t fully considered when he was first sentenced.
The appeal of James Erin McKinney could affect as many as 15 of Arizona’s 104 death row inmates. Attorneys say the Arizona courts used an unconstitutional test in examining the mitigating factors considered during the sentencing trials of the inmates.
McKinney wants the Supreme Court to throw out his sentences in the 1991 killings of Christine Mertens and Jim McClain so that a jury can decide whether he should face death or life in prison. He was first sentenced to death by a judge.
The Supreme Court has ruled both that juries, not judges, must impose death sentences, and that mitigating factors, including childhood deprivations, must be factored into sentencing decisions.
McKinney’s attorneys say the Arizona Supreme Court erred last year in upholding his sentences after a federal appellate decision concluded that the state court used an unconstitutional test in examining the mitigating factors considered during his sentencing.
Prosecutors said McKinney shouldn’t get a sentencing retrial, arguing his case was considered officially closed years before the 2002 Supreme Court decision that required death penalty decisions to be made by jurors, not judges.
Attorneys say the decision in McKinney’s case could affect other Arizona death row inmates who could challenge the test used in evaluating the mitigating factors considered during sentencing. But it’s unclear whether the ruling would affect death penalty cases from other states.
Jordon Steiker, a law professor at the University of Texas who filed a friend-of-the-court brief supporting McKinney’s position, said he doesn’t think the McKinney decision will have much of an effect on cases outside of Arizona.
But a brief filed by attorneys general in 16 other states said the changes that McKinney is seeking would represent a “sea change” that would make it harder to bring closure to death penalty cases.
In any case, Paul Bender, a professor of constitutional law at Arizona State University’s Sandra Day O’Connor College of Law, said there’s a strong case for letting juries decide sentencing retrials in cases like McKinney’s, but he doesn’t believe a majority of the court will agree with those arguments.
‘‘I don’t think there are five votes on the court to reverse a death penalty based on a technical issue,’’ Bender said.
McKinney and his half brother, Charles Michael Hedlund, were both convicted of murder in the deaths of Mertens and McClain during a series of burglaries in metro Phoenix. Hedlund also is on death row and has asked the Supreme Court to review his death sentence on similar grounds.
Prosecutors say both men beat and stabbed Mertens during a struggle at her home and that McKinney pinned Mertens to the floor and shot her in the back of the head.
About two weeks later, prosecutors say McKinney and Hedlund ransacked McClain’s home during a burglary and that one of them fatally shot McClain as he slept.
The Arizona Supreme Court, which had already upheld McKinney’s sentences in 1996, was asked by prosecutors to review his punishments again after the Ninth Circuit Court of Appeals concluded the state court applied an unconstitutional rule that required mitigating evidence, such as post-traumatic stress disorder, to be directed tied to the crime in order to be relevant at sentencing.
McKinney’s lawyers say their client suffered from post-traumatic stress because of a horrific childhood in which he was physically abused, frequently deprived of food and water, and locked outside the home with little clothing.
Prosecutors urged the court to uphold the 2018 state court review of McKinney’s sentences, saying his evidence of post-traumatic stress was considered by Arizona courts and that the review of his sentences didn’t reopen his case.
In upholding the sentences last year, the state’s highest court said it placed minimal weight on McKinney’s mitigation evidence, given the aggravating circumstances of the killings. The court said the crimes were planned and that McKinney had stated before Mertens’s shooting death that he would kill anyone he encountered during the burglary.
McKinney’s attorneys maintain that although his conviction was considered final in 1996, his case was reopened last year when the state Supreme Court reviewed his sentences.
McKinney’s attorneys also alleged the state court violated an earlier US Supreme Court ruling that concluded that the sentencer in a death penalty case can’t refuse to consider relevant mitigating evidence. They say the remedy for violating the rule was resentencing.
‘‘You shouldn’t be able to say that if it doesn’t have a connection to a crime, then it’s not really mitigation,’’ said Sharmila Roy, one of McKinney’s attorneys.
Yavapai County Attorney Sheila Polk, who wasn’t involved in the McKinney prosecution but is chairwoman of a prosecutors’ group that argued against his legal positions in a friend-of-the-court brief, said a ruling in McKinney’s favor would disrupt the finality that victims’ families have gotten through earlier verdicts and would ‘‘truly open up what we see an endless system of review and appeals in these cases.’’
The Arizona attorney general’s office, which is defending McKinney’s death sentences before the US Supreme Court, declined to comment.