By a 7-2 vote, the justices said state prosecutor Jim Williams improperly excluded blacks from the jury that convicted Allen Snyder of killing his estranged wife's companion. Snyder is black and the jurors were white.
Justice Samuel Alito, writing for the majority, said the trial judge should have blocked Williams from striking a black juror. Alito's opinion made no mention of Simpson.
Justices Clarence Thomas and Antonin Scalia dissented. Thomas said he would not "second-guess" the judge.
During jury selection in the trial, Williams disqualified all five blacks in the pool of prospective jurors. The Supreme Court ruled in 1986 that prosecutors may not exclude people from a jury solely because of their race. The court already had sent Snyder's case back to the Louisiana courts following a ruling in 2005 that bolstered the prohibition on race bias in jury selection.
The prosecutor's explanation for striking a prospective black juror was "suspicious," said Alito. The prospective juror's supervisor said he did not think a schedule conflict between the upcoming trial and the prospective juror's work would be a problem.
In contrast, the prosecutor accepted white jurors who disclosed conflicting obligations "that appear to have been at least as serious as" the prospective black juror who was excused, Alito wrote.
The trial took place in August 1996, less than a year after Simpson was acquitted of killing his ex-wife and a male friend of hers. Leading up to the trial, Williams made repeated public references to the Snyder case as his "O.J. Simpson case."
Snyder was convicted of first-degree murder in Jefferson Parish, just outside New Orleans. He was found guilty of repeatedly slashing his estranged wife, Mary Snyder, and a man, Harold Wilson, with a knife when he found them in a car outside her mother's home in August 1995. His wife survived, but Wilson died.
Adding to the Simpson comparison, Snyder told police just before his arrest that he was suicidal. Simpson, armed with a gun and apparently considering suicide, led police on a dramatic, televised chase before surrendering.
In a 4-3 decision, the Louisiana Supreme Court ruled that race had no part in the state's decisions involving black potential jurors.
When the case was argued in December, the justices were critical of the trial judge, Judge Kernan "Skip" Hand, for overruling many defense objections about the prosecutor's use of race and Simpson's name.
"Snyder v. Louisiana can't be seen in a vacuum," said CBS News chief legal analyst Andrew Cohen. "The Supreme Court over the past half dozen years has had a devil of a time getting lower courts in the South - especially but not limited to Texas - to abide by their rulings in capital cases. That's because the Justices have in recent years consistently, almost relentlessly, limited the ability of prosecutors and lower court judges to exclude blacks from serving as jurors to blacks in capital cases."
Stephen Bright, Snyder's Atlanta-based lawyer, said the ruling shows there is broad agreement among the justices that courts must closely examine the reasons given for excusing potential jurors when racial motives might be present but not acknowledged.
"The disturbing thing is that courts in Louisiana and elsewhere were just deferring to trial judges, no matter the reasons," Bright said.
Snyder will get a new trial as a result of the ruling, Bright said.