WASHINGTON -- The U.S. Supreme Court yesterday unanimously upheld the state of Ohio's revised policy for determining when especially dangerous inmates can be transferred to a "super-maximum security" prison in Youngstown, where they endure long periods of solitary confinement and little opportunity for exercise.

But in upholding Ohio's revised policy, which two lower federal courts found inadequate, Justice Anthony Kennedy's majority opinion made clear that prisoners earmarked for "supermax" status in Ohio and elsewhere have a constitutional right to be informed of the reasons for their reclassification and an opportunity to contest it.

In other action yesterday, the justices set aside the death sentence of a Texas murderer in an opinion that marked the high court's second rebuff of the New Orleans-based 5th U.S. Circuit Court of Appeals. That 6-3 decision was one of two rulings yesterday in which the court reaffirmed that it was unconstitutional for prosecutors to challenge prospective jurors on the basis of race.

Yesterday's decision in the "supermax" case frees the Ohio Department of Rehabilitation and Correction from a court order under which it had been providing prisoners not only with the protections required by the Supreme Court yesterday but also the right to call witnesses in contesting their transfer to the 500-bed "supermax" facility.

Kennedy said letting inmates call witnesses in their defense could undermine prison security and lead to reprisals against prisoners who testified.

Ohio will now be allowed to implement a revised policy for prisoner transfer that has been in legal limbo while the state appealed the lower-court rulings. That policy would replace Ohio's original transfer policy, which, according to Kennedy's majority opinion, involved "inconsistent and undefined" procedures that resulted in "haphazard" placement of inmates in cells where a light burns 24 hours a day and conversation between prisoners is impossible.

Both sides in the case saw yesterday's decision as a victory.

Ohio Solicitor Douglas R. Cole, the state's top courtroom lawyer, said he was "very pleased with the ruling" and asserted that the court had upheld the state's revised policy "as written."

University of Pittsburgh law professor Jules Lobel, who represented the prisoners, said: "On the basic issue in this case, the court sided with us. That basic issue was whether prisoners who are put in this type of facility have any liberty interest whatsoever."

In setting aside the death sentence of Texas death row inmate Thomas Joe Miller-El, the justices yesterday ruled 6-3 that Miller-El's rights were violated when prosecutors used peremptory challenges -- those which by tradition do not require an explanation -- to exclude 10 African Americans from the jury that tried Miller-El for the 1985 robbery-murder of a hotel employee in Dallas.

In 2003, the Supreme Court overturned a ruling by the 5th Circuit that Miller-El couldn't file a writ of habeas corpus based on a claim that jury selection in his trial was tainted by racial discrimination. It returned the case to the 5th Circuit, which again found against Miller-El, a ruling overturned yesterday. Miller-El will now get a new trial.

In his majority opinion, Justice David H. Souter said, "The prosecutors' chosen race-neutral reasons for the strikes do not hold up and are so far at odds with the evidence that pretext is the fair conclusion."

Souter noted that prosecutors took their cues from a 20-year-old manual of tips on jury selection that contained racial stereotypes and "shuffled" the order in which prospective jurors would be interviewed to increase the chance that whites would be chosen.

Souter was joined by Kennedy and Justices John Paul Stevens, Sandra Day O'Connor, Ruth Bader Ginsburg and Stephen Breyer.

Justice Clarence Thomas, joined by Chief Justice William H. Rehnquist and Justice Antonin Scalia, wrote a dissenting opinion in which he said. "Miller-El has not established, much less established by clear and convincing evidence, that prosecutors racially discriminated in the selection of his jury."

In another ruling involving peremptory challenge, the justices ruled 8-1 that a defendant claiming racial bias in jury selection need not demonstrate that "it is more likely than not" that prosecutors were racially biased before the trial judge must ask the prosecution to offer non-racial reasons for striking jurors of a particular race.

The case concerned Jay Shawn Johnson, a black man convicted in California of murdering a 19-month-old white child. When Johnson's attorney complained that prosecutors had challenged all three blacks in the jury pool, resulting in an all-white jury, The trial judge refused to ask the prosecutor to offer a non-racial explanation of the challenges, finding that under California law, the defense hadn't established a "prima facie" case of discrimination. That ruling was upheld by the California Supreme Court.

Writing for the majority, Stevens said the proper definition of "prima facie" was a pattern of jury challenges that led to "inferences that discrimination may have occurred." At that point, prosecutors must be asked to produce non-racial explanations for challenging the jurors.

Stevens was joined by all other justices except Thomas.

In other action, the court sent back to a lower court the question of whether an Ohio man sentenced to death in the murder of a robbery victim can challenge his sentence based on the fact that the prosecution in a separate trial identified both him and an accomplice as the triggerman. In an opinion by O'Connor, the court unanimously remanded that issue to lower courts while overturning the 6th Circuit's finding that John David Stumpf's conviction was compromised by the inconsistent theories about who actually shot Mary Jane Stout -- Stumpf or Clyde Daniel Wesley, who also was convicted of murder but wasn't sentenced to death.