(CN) - "Federal courts may not issue writs of habeas corpus to state prisoners whose confinement does not violate federal law," the Supreme Court ruled Monday, overturning a federal appeals court's ruling for an Indiana man convicted of shooting and killing four men.
In a seven-page, unsigned opinion, the justices unanimously vacated the 7th Circuit's grant of habeas relief to Joseph Corcoran, who was convicted of killing four men, including his brother and his sister's fiancé.
The trial judge imposed the death penalty, partially relying on aggravating factors that the Indiana Supreme Court said were not authorized by state law, including the innocence of the victims and the heinousness of the crime.
The trial court issued a revised ruling that explained its sentencing decision in a way that satisfied the state high court.
Corcoran then challenged his sentencing in federal court, again arguing that the trial judge had relied on impermissible aggravating factors.
But the federal judge granted Corcoran's petition on a different ground: that the prosecutor violated the Sixth Amendment by offering to take the death penalty off the table to avoid a jury trial.
The 7th Circuit initially denied and later granted his habeas petition on remand from the U.S. Supreme Court, saying the trial court needed to reconsider the death penalty to "prevent non-compliance with Indiana law."
"But it is only noncompliance with federal law that renders a state's criminal judgment susceptible to collateral attack in the federal courts," the Supreme Court ruled (emphasis in original).
"The habeas statute unambiguously provides that a federal court may issue the writ to a state prisoner 'only on the ground that he is in custody in violation of the Constitution or laws or treaties of the United States.'"
The 7th Circuit's ruling "contained no hint that it thought the violation of Indiana law it had unearthed also entailed the infringement of any federal right," the justices wrote.
The federal appeals court tried to correct this flaw by amending its opinion to state that Corcoran's habeas petition had invoked federal law.
"The amendment did not cure the defect," the Supreme Court wrote. "It is not enough to note that a habeas petitioner asserts the existence of a constitutional violation; unless the federal court agrees with that assertion, it may not grant relief" (emphasis in original).
The Supreme Court vacated the grant of habeas relief and remanded.
"We express no view about the merits of the habeas petition," the justices added.
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