The U.S. Supreme Court Monday agreed to hear Texas' challenge of a Fifth Circuit decision to allow a man's successive habeas claim under a rare exception for "previously unavailable" claims under the Antiterrorism and Effective Death Penalty Act of 1996.

AEDPA generally bars state prisoners from filing successive habeas applications, with some exceptions. The parties told the high court that this case involves one of the rarer exceptions, which allows claims that rely on "a new rule of constitutional law, made retroactive to cases on collateral review by the Supreme Court, that was previously unavailable."

Texas contends that the Fifth Circuit erred in allowing Dexter Johnson, who is on death row, to file a successive habeas application raising a claim that he should be spared from execution because he has an intellectual disability. He did not raise the claim in his first federal habeas petition because he did not fit the diagnostic criteria for intellectual disability at the time, but the criteria changed just before his petition was denied.

The Lone Star State argued that the claim was technically available to Johnson, even though it would have failed at the time. Johnson's attorneys contended that a claim with no chance of success is not "available."

Texas' granted petition asks whether "a claim relies on a 'a new rule of constitutional law, made retroactive to cases on collateral review by the Supreme Court, that was previously unavailable' when the habeas petitioner could have asserted a claim based on the rule in a prior federal habeas petition."

At issue is Johnson's claim under the high court's 2002 decision in Atkins v. Virginia , which found executions of people with intellectual disabilities violates the Eighth Amendment's prohibition on cruel and unusual punishments.

In Johnson's case, a jury found him guilty of capital murder in 2007 for kidnapping, raping and murdering a woman. He was 18 at the time of the killing.

Johnson's defense had presented expert testimony that he had the intellectual functioning equivalent to a 10-year-old, but the expert said Johnson did not have an intellectual disability based upon the diagnostic criteria at the time because his IQ was higher than 70.

This made a claim under Atkins impossible then, and Johnson's court-appointed counsel did not raise an Atkins claim in state habeas proceedings, attorneys told the high court in briefing. Texas' highest criminal court, the Court of Criminal Appeals, affirmed his conviction and sentence and denied his initial state habeas petition. The U.S. Supreme Court denied his petition for certiorari.

In 2011, Johnson filed a federal habeas petition that also did not raise an Atkins claim or assert an intellectual disability. But while the petition was pending, in May 2013 a new edition of the Diagnostic and Statistical Manual of Mental Disorders — the DSM-5 — was published.

The manual, which sets psychiatric professional standards for diagnosing mental disorders, contained changes that reflected a new recognition that those with IQ scores over 70 could still be intellectually disabled.

The federal court denied Johnson's petition in August 2013. The Fifth Circuit affirmed, and the U.S. Supreme Court denied certiorari again.

Johnson was scheduled for execution in May 2019. Months beforehand, the district court appointed the Federal Public Defender to represent Johnson after he raised concerns about his attorney.

Two weeks before his execution date, he filed a state habeas application raising an Atkins claim based on an evaluation performed by a new expert. The doctor found Johnson had an IQ score of 70 and qualified as intellectually disabled.

But the Texas Court of Criminal Appeals tossed his application a week later, saying the new Atkins claim should have been raised in the earlier petition. The next day, though, a federal judge stayed Johnson's execution over the public defender's concerns about his counsel.

His new public defenders filed another state habeas petition raising an Atkins claim with additional evidence, including a comprehensive forensic neuropsychological report and other testimony and evidence that was not included with the previous filing. The state courts dismissed the petition.

Johnson's attorneys also sought the Fifth Circuit's authorization to file a successive federal habeas application. The Fifth Circuit allowed the filing and granted a further stay of execution.

In 2022, a federal district court found that Johnson met AEDPA's successive-petition requirements and allowed his Atkins claim to go forward.

The district court certified one of Johnson's questions for interlocutory review: Whether there can be judicially created exceptions to 28 U.S.C. § 2244(b)(2)(A).

The Fifth Circuit accepted the appeal last year and reaffirmed its 2017 holding in In re: Cathey , which holds that AEDPA's "previously unavailable" rule requires courts to explore whether the claim could have been meritorious at the time of the earlier federal habeas proceedings.

Texas filed its petition for certiorari in January, telling the high court that circuits are split over when to consider new rules were actually available in habeas cases.

The Fifth and Ninth Circuits have held that a claim is only available if it had "some possibility of merit" based on the evidence available at the time of the earlier petition. The Fourth and Eleventh Circuits, meanwhile, do not consider the potential merit of the earlier claim, only consider whether the rule could have been previously raised, Texas argued.

But Johnson told the high court that Texas has overblown the purported circuit split, that the issue was rare enough that it was not worth justices' time, and that the timing was awkward because Texas' petition stems from an interlocutory appeal over a different question.

The circuits at issue all apply a feasibility standard that considers the circumstances of the previous petition to determine whether the claim was actually available, he argued in a reply brief.

"The lower courts [Texas] claims disagree have all rejected a strict rule in favor of this pragmatic approach," he said.

The brief said the key differences between the circuits can be attributed to the timing of the claims rather than the merits.

Also, Johnson said his is an exceptionally rare case: He is one of only two petitioners in the nearly three decades of AEDPA's existence who have received circuit authorization for a successive petition under the standard at issue.

He pointed to Texas' petition, which said this case "may well present the only vehicle to resolve the issue."

"That assertion underscores that the question presented is not recurring," Johnson said. "And it shows that it is not worth this court's time and resources to resolve."

The high court's decision Monday to grant Texas' petition comes weeks after the justices took the unusual step of declining to rule after oral arguments in Hamm v. Smith , another capital case involving IQ tests and the death penalty.

Texas is represented by Ken Paxton, Brent Webster, William Peterson, William Cole, Cameron Fraser and Gwendolyn Vindell of the Office of the Texas Attorney General.

Johnson is represented by Jason Hawkins, Jeremy Schepers, and Joe Hamrick of the Office of the Federal Public Defender.

The case is Eric Guerrero v. Dexter Johnson, case number 25-1003, in the Supreme Court of the United States.

--Editing by Brian Baresch.