WASHINGTON (AP) — The Supreme Court said Thursday that a federal appeals court was wrong when it ordered Michigan to retry or release a convicted murderer because his rights were violated when he was shackled at trial.

In a decision that split the court 6-3 along ideological lines, the court’s conservative majority said that a federal appeals court was wrong to apply only one legal test to conclude that the man should be released or retried. The justices said the appeals court should have applied two different legal tests, not just one, and that the man’s case didn’t pass the second test.

State courts had agreed that shackling Ervine Davenport at his trial violated his rights but said the error was harmless because it did not affect the verdict in his case. Davenport then took his case to federal court, and an appeals court concluded he should be released or retried.

Writing for the majority, Justice Neil Gorsuch disagreed. He said that: “When a state court has ruled on the merits of a state prisoner’s claim, a federal court cannot grant relief without first applying both” a test the court outlined in a 1993 Supreme Court case and a second one Congress mandated when it passed a 1996 law, the Antiterrorism and Effective Death Penalty Act. The law made it more difficult for prisoners to challenge their convictions.

Gorsuch wrote that even assuming Davenport succeeded under the 1993 test, he failed the second because the Michigan Court of Appeals had not acted unreasonably in deciding the case. Gorsuch noted that the court had found Davenport’s shackling “harmless for two reasons,” because of the overwhelming evidence against him and because jurors said it did not affect their verdict.

But Justice Elena Kagan, writing for herself and the court’s two other liberal justices, said requiring courts to apply both tests was “make-work.” She said the court had twice in recent years said that applying the 1993 test alone is sufficient because it is “harder for a prisoner to meet.” She wrote that requiring courts to do both tests is a “pointless demand.”

Michigan Solicitor General Fadwa Hammoud, who argued the case for the state, said the high court’s decision “ensures that state court decisions that determine an error at trial was harmless beyond a reasonable doubt are given the deference and respect they are due — not just in Michigan, but across the country.”

Messages left for Davenport’s attorney were not immediately returned.

Davenport’s case traces back to the 2007 death of Annette White. The two had been attending a gathering together and left in a car. Both had used cocaine, and White died during a struggle while the two were driving. Davenport said White had attacked him. A jury convicted him of murder and sentenced him to life in prison.

Davenport appealed, arguing that his rights were violated because he was shackled during his trial at the waist, wrist, and ankles. Five of the twelve jurors said they remembered seeing the shackles, but all said the shackles did not affect their deliberations. State courts concluded that Davenport’s shackling didn’t affect the case’s outcome.

A federal appeals court, however, said the restraints “branded Davenport as having a violent nature” and were “inherently prejudicial.” It ordered Michigan to retry Davenport or release him. The high court reversed that decision.

The case is Brown, Acting Warden v. Davenport, 20-826.

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