WASHINGTON (AP) -- A federal law says states and localities with a history of discrimination cannot change any voting procedures without first getting approval from the Justice Department or a federal court in Washington. Yet Texas is asking the Supreme Court to allow the use of new, unapproved electoral districts in this year's voting for Congress and the state Legislature.

The outcome of the high court case, to be argued Monday afternoon, could be another blow to a key provision of the Voting Rights Act. In 2009, the justices raised doubts about whether Southern states still should need approval in advance of voting changes more than 40 years after the law was enacted.

The case also might help determine the balance of power in the House of Representatives in 2013, with Republicans in a stronger position if the court allows Texas to use electoral districts drawn by the GOP-dominated Legislature.

The complicated legal fight over Texas' political maps arises from the state's population gain of more than 4 million people, most of them Latino or African-American, in the 2010 census, and involves federal district courts in Texas and Washington, as well as the Supreme Court. It has come to a head now because Texas needs to be able to use some maps to hold elections this year.

The state has so far failed to persuade three judges in Washington, including two appointees of Republican President George W. Bush, to sign off on new political maps adopted by the Legislature. The justices jumped into the case at Texas' request after judges in San Antonio who are hearing a lawsuit filed by minority groups drew their own political lines for use in the 2012 elections.

Texas Attorney General Greg Abbott, a Republican, said Monday "the judges disregarded the will and sovereign power of the state of Texas."

Texas Republicans were in complete control of the redistricting process that is required following the once-a-decade census. They faced the happy prospect of adding four new congressional seats by virtue of Texas' huge population gain since the last census in 2000. Texas will have 36 seats in the 435-member U.S. House next year.

Republican lawmakers in Austin, the Texas capital, did what majority parties in statehouses across the country do when given such an opportunity: They made the most of it, drawing maps for the state House and Senate, and the U.S. House aimed at maximizing Republican gains.

To do this they carefully distributed Democratic voters, including Latinos and African-Americans.

But Latino and African-American groups, as well as the Texas Democratic Party, complained that the result ran afoul of the Voting Rights Act's prohibition against diluting the ability of minorities who had suffered under official discrimination from electing representatives of their choice.

The opponents of the new maps had a powerful piece of evidence because Latinos and African-Americans accounted for nearly all the growth in Texas' population.

A divided court in San Antonio drew maps that differed from the Legislature's efforts, giving Democrats a chance to prevail in three or four more congressional districts. Republicans now represent 23 of the 32 current districts.

The narrow legal question for the Supreme Court is whether the judges in Texas went too far in crafting their own plans, unwilling to use the state's maps as starting points. If the court agrees with the state on this point, it then would have to decide what maps to use.

Even without the Washington court's approval, Texas says it should be able to use its own maps just for this year because time is running short before primary elections, already delayed from March to April 3.

But the minority groups, as well as the Obama administration, say such an outcome is strictly forbidden by the Voting Rights Act and would, in essence, eviscerate the law's most potent weapon, its Section 5 requirement of advance approval, also known as preclearance.

Pamela Karlan, a Stanford University law professor who is working with Latino and other minority groups that oppose the state maps, said a court ruling allowing the Texas maps to be used "would be a major retreat from the way Section 5 has operated up till now."

The 1965 law has been the government's chief weapon against racial discrimination at polling places for nearly a half-century. Section 5 requires all or parts of 16 states - mainly in the South and with a history of discrimination in voting - to get Justice Department or court approval before making changes in the way elections are conducted.

According to the Justice Department Web site, Section 5 currently applies to the states of Alabama, Alaska, Arizona, Georgia, Louisiana, Mississippi, South Carolina, Texas and Virginia. It also covers certain counties in California, Florida, New York, North Carolina and South Dakota, as well as some local jurisdictions in Michigan and New Hampshire. Preclearance coverage has been triggered by past discrimination not only against blacks, but also against American Indians, Asian-Americans, Alaskan Natives and Hispanics.

In the 2009 case, also from Texas, the court avoided deciding whether the advance approval requirement is constitutional in an era marked by dramatic civil rights gains and the election of the first African-American president. That larger issue, Chief Justice John Roberts said, "is a difficult constitutional question we do not answer today."

The constitutional issue also is not directly raised in the current case, but lawsuits from Alabama and North Carolina that ask to strike down the provision could find their way to the Supreme Court. In the past four months, U.S. District Judge John Bates in Washington threw out both challenges to the law after finding that discrimination in voting continues to this day and that Congress properly passed legislation to address the problem.

Both rulings have been appealed to the U.S. Court of Appeals for the District of Columbia Circuit, which has set a Jan. 19 argument for the Alabama case and Feb. 27 for the North Carolina case.

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