Washington ? The Supreme Court warned prosecutors on Monday to use care in striking minorities from juries, siding with black murder suspects in Texas and California who contended that their juries had been unfairly stacked with whites.

Justice Clarence Thomas, the only black member of the high court, voted against both suspects.

The court used the cases to bolster its landmark 1986 decision barring prosecutors from disqualifying potential jurors based on their race.

“The court is sending a very strong message that racial discrimination in jury selection is not to be tolerated,” said Stephen Bright, director of the Southern Center for Human Rights.

Justice Stephen Breyer suggested a radical change in the way juries are picked. He said that the only way to get discrimination out of jury selection may be to stop letting prosecutors and defense lawyers dismiss some potential jurors without giving a reason.

That suggestion was made by the late Thurgood Marshall, the first black justice, and Breyer seemed to launch a lobbying effort for it.

The rulings, in the final three weeks of the Supreme Court’s term, came in appeals filed by indigent black inmates in Texas and California.

In the Texas case, the court ordered a new trial for death row inmate Thomas Miller-El, who had been convicted for the 1985 murder of a 25-year-old Dallas motel clerk. It was the second time the justices had reviewed his case.

Justice David H. Souter, writing the 6-3 decision, said there was strong evidence of prejudice during jury selection. He noted that black jurors were questioned more aggressively about the death penalty, and the pool was “shuffled” at least twice by prosecutors, apparently to increase the chances whites would be selected.

“At least two of the jury shuffles conducted by the state make no sense except as efforts to delay consideration of black jury panelists,” Souter said, adding that it “blinks reality” to deny jurors were struck because they were black.

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

Miller-El contends that Dallas County prosecutors had a long history of excluding blacks from juries and pointed to training manuals that were distributed to prosecutors from the 1960s into the early 1980s.

The manuals advised prosecutors to remove blacks or Jews from death penalty juries on the theory that those groups would be more sympathetic to criminal defendants.

At trial, Miller-El was convicted by a 12-member jury that included one black. Prosecutors struck nine of the 10 blacks eligible to serve.

Thomas issued a 36-page dissent, which was longer than Souter’s opinion, arguing that Texas prosecutors had offered enough evidence that exclusions were made for reasons other than race.

In the other case, justices ruled 8-1 that California courts had made it too hard for defendants to claim racial bias in jury selection. Justices said courts should reconsider the case of a black man, Jay Shawn Johnson, who was convicted of second-degree murder in the death of his white girlfriend’s baby. The jury was all white.

Stevens said that the California legal standard for jury bias claims, that a defendant must show that it is “more likely than not” that prosecutors discriminated in selecting jurors, was “an inappropriate yardstick.” Defendants must only show evidence that infers discrimination, the court found.

In a brief dissent, Thomas said a state has “broad discretion to craft its own rules of criminal procedure.”

In other cases, the court:

¢ Declined to be drawn into a dispute over President Bush’s power to detain U.S. terror suspects in case of “dirty bomb” suspect Jose Padilla. His case is currently under review in the lower courts.

¢ Turned away several appeals from broadcast and newspaper groups that sought to restore new government rules easing restrictions on media ownership.

¢ Ruled unanimously that new Ohio rules give inmates a fair opportunity to fight transfers to super maximum-security prisons.