PHOENIX - A bid by Republicans to upend the state's 30 legislative districts could be bolstered - thrown out of federal court - because of the actions of the U.S. Supreme Court.

In an order Monday, the three-judge panel hearing the challenge to the lines said it wants attorneys to tell it what effect last month's ruling on the federal Voting Rights Act has on the case. The high court concluded the formula used to require Arizona and other states to get federal "preclearance" of voting law changes - including redistricting lines - is illegal.

That could prove significant.

Attorneys for the Independent Redistricting Commission have conceded the 30 districts it drew do not have equal population, but argued the variances were necessary to make sure there were enough districts where minority voters had the chance of electing someone of their choice.

It said having a sufficient number of such districts was necessary to ensure Arizona could get the district lines precleared by the U.S. Justice Department.

If the need for preclearance was legally unnecessary, then a key reason for the unequal districts disappears.

Hanging in the balance could be the political makeup of the Legislature through the end of the decade. Before 2012, Republicans had 21 of the 30 Senate seats and a 40-20 edge in the House. Last year's election, after redistricting, narrowed those leads to 17-13 and 36-24, respectively.

If the judges agree with challengers, the judges likely would order the commission to redraw the lines for the 2014 race, with directions as to what it can and cannot do.

Joe Kanefield, one of the commission's attorneys, said late Monday he is still studying the order. Kanefield said he will argue that what the Supreme Court did last month is legally irrelevant to this case.

Last month the Supreme Court overturned a section of the 1965 Voting Rights Act that created a formula to determine which states and counties have a history of discrimination and, therefore, must submit any alterations in voting laws to the Justice Department for "preclearance." Arizona was included.

While the justices told Congress it is free to come up with a new formula that reflects current conditions, as of now, there is no preclearance.

However, Kanefield said preclearance was in effect in 2011. "So compliance ... was certainly a legitimate goal of the commission," he said.

Attorney David Cantelme, representing challengers, sees it differentlt.

"The heart of their defense is the Voting Rights Act," he said, saying the ruling "really affects Arizona."

The danger for the Republican challengers in Monday's order is the judges want to know if the elimination of the section of the Voting Rights Act means the case should not be in federal court, but rather before a state judge - something Cantelme said he will fight.

The lawsuit contends the commission deliberately sought to create as many safe Democratic districts as possible by pushing as many Republicans as possible into GOP-dominated districts. He said the commission did that by overpopulating GOP districts and underpopulating the Democratic ones.

As an example, he cited District 8, which runs from Oracle and San Manuel through Coolidge and Florence into the San Tan Valley and up through Globe. Democrats have a 10-point registration edge over Republicans. To create that imbalance, Cantelme said the commission drew lines that eliminated Republican voters, even though it meant the population was 4,600 below the average.

Mary O'Grady, another commission attorney, said beyond the federal requirements in place at the time, the 2000 voter-approved state constitutional amendment creating the commission requires it to meet other goals, including creating as many politically competitive districts as possible.