WASHINGTON (CNN) -- The Supreme Court threw out a Louisiana man's murder conviction and death sentence on Wednesday, citing the prosecutor's exclusion of blacks from the jury.
Justice Samuel Alito wrote the majority opinion in a case reversing a capital conviction on grounds of racial bias.
The 7-2 ruling was a sharp rebuke of prosecutors and their use of pre-emptive challenges to keep blacks off the jury.
"The trial court committed clear error," wrote Justice Samuel Alito.
In granting Allen Snyder a new trial, the high court's decision focused almost entirely on the exclusion of one potential juror, an African-American. But the case involved broader accusations of misconduct involving race.
In oral arguments in December, the justices also had tough words for the defense attorney and the trial judge overseeing the case. Snyder was convicted in what Alito called an "incredibly short trial." The trial lasted only 3˝ days from the beginning of jury selection to the verdict.
Snyder was sent to death row for the murder of his estranged wife's companion, Harold Wilson, outside New Orleans, Louisiana. Snyder used a knife to attack the couple as they sat in their car after a date. Mary Snyder was severely wounded in the attack but survived.
Allen Snyder pleaded not guilty by reason of insanity.
In remarks to reporters in the weeks before the trial, senior prosecutor Jim Williams repeatedly referred to it as "my O.J. Simpson case."
He referred to Simpson again during jury selections, but promised to stop doing so after the defense raised objections. He did mention it again, however, in his closing argument.
While the Simpson remarks dominated oral arguments in December, Alito chose in Wednesday's ruling to focus on the fact that five African-Americans in the jury pool were struck by the prosecution.
Supreme Court precedent forbids race being used as the sole reason when issuing peremptory challenges.
"Racial prejudice infected the selection of the jury," Snyder's attorney, Stephen Bright, said during oral arguments.
"All the O.J. Simpson case does is put a little icing on the cake. The evidence is too powerful. It all points in one direction and that's intentional race discrimination. And if that happened, Allen Snyder is entitled to a new trial."
The case reflected a measure of frustration among the high court justices, who were handling it for a second time. The Louisiana Supreme Court allowed the initial conviction and death sentence to stand after being told by the U.S. Supreme Court to take another hard look at the fairness of the trial.
One black juror candidate -- Jeffrey Brooks, a student -- was excluded because he initially was worried that missing class would hurt his degree requirements. But a white candidate was kept on the panel, even though he had complained about having a sick wife and other pressing personal problems.
The white man was assured the trial would be speedy, and the black man's dean assured the court the student's class work would not be unduly affected. Nevertheless, the white man stayed on the jury; the black man was excluded.
Alito said the prosecution's reasons for excluding Brooks were "suspicious."
"The implausibility of this explanation is reinforced by the prosecutor's acceptance of white jurors who disclosed conflicting obligations that appear to have been at least as serious as Mr. Brooks'," he noted.
In dissent, Justice Clarence Thomas criticized the majority for "paying lip service" and "second-guessing" the discretion of state trial courts. He was supported by Justice Antonin Scalia.
The majority offered no explanation why it chose not to focus on the O.J. Simpson aspect in the decision.
Alito's colleagues seemed dismayed when told the trial judge repeatedly overruled defense objections when race was used by the prosecutor, including the mention of Simpson who was acquitted in a 1995 criminal trial of murdering his former wife and her companion.
In arguments, Justice David Souter was biting in his assessment of the judge's performance.
"This is not a critical mind at work, is it?" he said, which drew nervous laughter in the courtroom.
Jefferson Parish is about 20 percent black, but African-Americans make up only 11 percent of jurors called in criminal cases, which Ruth Bader Ginsburg had pointed out is "almost half of what you'd expect." E-mail to a friend