The Supreme Court has thrown out electoral maps drawn by federal judges in Texas that favored minorities. The unsigned opinion Friday left the fate of Texas' April primaries unclear.

The justices ordered the three-judge court in San Antonio to come up with new plans, but did not compel the use of maps created by Texas' Republican-dominated state legislature. Only Justice Clarence Thomas said he would have gone that far.

Controversy over the maps arose from redrawing political boundaries based on results of the 2010 census that found that Texas added more than 4 million new residents, mostly Latinos and African-Americans, since 2000. The minority groups complained they were denied sufficient voting power by Republican lawmakers who sought to maximize GOP electoral gains in violation of the landmark Voting Rights Act.

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