WASHINGTON -- The U.S. Supreme Court indicated yesterday that it will continue to maintain a hard line against prosecutors who exclude members of racial minorities from juries using peremptory challenges, which ordinarily don't require an explanation for striking a prospective juror.

Several justices seemed troubled that California prosecutors were able to use peremptory challenges to remove all three African-Americans in a pool used to choose a jury in the trial of Jay Shawn Johnson, a black man convicted of murdering the 18-month-old daughter of his white girlfriend and another man.

"The prosecutors excluded all three black jurors and left a black defendant to face an all-white jury in a racially tinged case," Johnson's lawyer, Stephen B. Bedrick, told the court. Bedrick said Johnson's conviction couldn't be squared with Batson v. Kentucky, a landmark 1986 ruling in which the U.S. Supreme Court said peremptory challenges could not be used to exclude members of a particular race.

Under the Batson ruling, a defendant who objects to the prosecution's peremptory challenge of jurors must make a "prima facie" case of purposeful racial bias in jury selection. At that point, the prosecution is supposed to offer non-racial reasons for the challenges -- such as that a potential juror was suspected of being unsympathetic to the prosecution. Finally, the defendant must prove that there was improper discrimination even in light of the prosecution's explanation.

In Johnson's case, the judge ruled that the defendant hadn't made a showing of obvious racial discrimination because, even without the prosecution coming forward to offer justifications, there were apparent non-racial explanations for two of the three challenges. (For example, one prospective juror had a sister who had been arrested on drug charges and might be hostile to the government's case.)

"The purpose of Batson is to elicit reasons [for challenges] from a prosecutor," Bedrick argued to the high court. "Batson won't work unless reasons are given."

But California Deputy Attorney General Seth K. Schalit told the justices that the judge in Johnson's case did not violate the Batson decision. He also defended the California Supreme Court's holding that, to make the beginnings of a case contending discrimination -- and thus trigger the requirement that prosecutors offer a non-racial reason for excluding a juror -- the defendant must convince the judge that "it is more likely than not" that there was a racial motive for the exclusion.

Although Schalit said the California rule was "consistent with Batson," several justices seemed to believe that it gave too narrow a reading of the Batson decision's language about a "prima facie" showing of discrimination -- that is, one that is apparent even before closer inspection.

Justice Anthony Kennedy suggested that under the Batson ruling, a trial judge could take a generous view of the prima facie requirement, meaning that all that a defendant would need to show is that all members of a racial group were challenged. At that point, the trial judge would solicit, scrutinize and, in some cases, accept the prosecution's non-racial explanation. "If the threshold at step 1 is easier to cross, we can make the inquiry at step 2 more rigorous," Kennedy said.

Yesterday's arguments were highly technical, with the justices and lawyers debating whether the legal term "prima facie" -- Latin for "at first view" -- can be defined differently in various legal contexts.

But the issue of racial discrimination in jury selection has remained a source of controversy in the criminal-justice system in Pennsylvania and elsewhere across the nation, despite the Batson decision.

Several justices indicated yesterday that the court meant what it said in 1986. When Schalit suggested that prosecutors were put at a disadvantage when they were forced to explain reasons for their peremptory challenges, Justice Antonin Scalia shot back: "You can't make peremptory challenges for any reason [you want]. Once you acknowledge that, what's the harm to having people come up to court and explain their reasons?"

In other business yesterday, the court:

Agreed to hear an appeal by the U.S. Justice Department of a lower court's ruling in favor of a religious group in New Mexico that uses a herbal tea containing dimethyltryptamine, a hallucinogenic controlled substance. The Denver-based 10th U.S. Circuit Court of Appeals ruled that the group, known as O Centro Espirita Beneficiente Uniao Do Vegetal, is protected by a 1993 federal law known as the Religious Freedom Restoration Act.

Said it would decide whether a property occupied by two residents can be searched with the permission of only one. The justices will review a ruling by the Georgia Supreme Court that police violated the Fourth Amendment when they searched a home for cocaine with the approval of a woman who said her husband was using the drug.

Declined to review a decision of the 1st U.S. Circuit Court of Appeals in Boston upholding a Massachusetts law creating a 6-foot buffer zone around patients who are within 18 feet of the entrance to an abortion clinic. Anti-abortion groups had claimed that the buffer zone violated the free-speech rights of "sidewalk counselors."