WASHINGTON (AP) _ The Supreme Court today waded into a politically sensitive dispute over alleged racial bias and selective prosecution in crack-cocaine cases.

The justices said they will review rulings that threw out federal indictments against five men who had been charged with trafficking in crack in the Los Angeles area.

The men contended that they were chosen for federal prosecution because they are black, and federal prosecutors initially refused to rebut the allegations.

The issue in the nation's highest court is not whether racially biased prosecution took place, but whether lower courts wrongly required the federal government to combat the selective-prosecution allegations.

In other action today, the Supreme Court:

_Made it harder to uphold a death sentence if errors occurred during the sentencing and ordered a new review of a Virginia death row inmate's case.

_Refused to reinstate a Georgia law that allowed grandparents to win court-ordered visitation with their grandchildren over objections from the child's parents.

_Left intact the conviction of a Mexican businessman sentenced to life in prison for his role in the 1985 kidnap, torture and murder of a U.S. Drug Endorcement Administration agent in Guadalajara, Mexico.

The five men in the selective prosecution case _ Christopher Armstrong, Aaron Hampton, Freddie Mack, Shelton Martin and Robert Rozelle _ were charged with participating in the distribution of cocaine base, commonly called crack, in 1992.

The charges stemmed from a joint investigation by Inglewood, Calif., police and federal drug agents.

The decision to charge the five men with federal, rather than state, crimes was significant. Federal law imposes a minimum sentence of 10 years and a maximum of life for those convicted of selling more than 50 grams of crack. Under California law, however, the sentence for that crime ranges from three to five years.

To support their selective-prosecution claim, the five defendants pointed to a study of every crack prosecution closed by the local federal public defendant's office in 1991. In all 24 such cases, the defendants had been black.

A federal judge granted the defendants' ``discovery'' request and ordered prosecutors to provide further racial data and explain how they chose which crack cases to pursue in federal court.

The government chose not to comply with that order, and instead appealed to the 9th U.S. Circuit Court of Appeals.

The appeals court upheld the judge's order and subsequent dismissal of the indictments against the five men.

The 9th Circuit court ruled that the defendants had presented facts ``which establish a colorable basis to believe that the government has engaged in selective prosecution.''

Only expert testimony about the prosecution's decision-making and motivation could rebut that, the appeals court said.

In the appeal acted on today, Clinton administration lawyers argued that the defendants should have been _ but were not _ required to show that some crack traffickers avoided federal prosecution because they are not black.

The government lawyers said the 9th Circuit court ruling will result in ``impeding prosecutions and delaying trials on the merits.''

The selective-prosecution dispute is distinct from the national debate over the federal policy of punishing crack-cocaine offenders much more harshly than those caught with the powdered variety of the drug.

The debate involves race and economic class. Crack is known as an inner-city drug while cocaine powder is used more often in the suburbs.

The case is U.S. vs. Armstrong, 95-157.