WASHINGTON - The Supreme Court sided with black challengers Wednesday and told a lower court to reconsider whether a redistricting plan drawn by Alabama's Republican legislature packed minority voters into districts in order to dilute their influence.

The court voted, 5-4, to send the plan back for further judicial review. Justice Stephen Breyer wrote the opinion, and Justice Anthony Kennedy sided with the court's liberals to make up the majority.

The challenge was brought by black officeholders and Democrats who argued that the state's Republican leadership packed minority voters into districts that allowed the election of African American officials but reduced their influence elsewhere.

Breyer said a lower court panel should have looked at individual districts rather than statewide in order to decide whether there was racial gerrymandering. And he said the legislators and the reviewing court did not use the proper test in deciding whether the redistricting was in line with the Voting Rights Act.

The act forbids "retrogression" in districts that favor minority candidates. But that doesn't mean that the districts must retain a previous percentage of minority voters to meet the standard, Breyer wrote.

What's important instead is looking at what percentages are necessary to preserve the minority's ability to elect the candidate of its choice, he said.

"Asking the wrong question may well have led to the wrong answer," Breyer wrote.

The court's jurisprudence on when race can be used in drawing legislative districts is complex and at times contradictory. And more than one justice pointed out during oral arguments that minority voters used to come to the court to demand that legislatures specifically use race to ensure that blacks and Hispanics be represented in government.

The court's four most consistent conservatives - Chief Justice John Roberts and Justices Antonin Scalia, Clarence Thomas, and Samuel Alito - said the decision could have implications far beyond the limited ruling the majority professed.

"The court issues a sweeping holding that will have profound implications for the constitutional ideal of one person, one vote, for the future of the Voting Rights Act of 1965, and for the primacy of the state in managing its own elections," Scalia wrote in a dissent that all joined.

Thomas, the court's only African American member, wrote separately to say that the intent of the Voting Rights Act has been "hijacked" by the Justice Department and the American Civil Liberties Union.