By Ariane de Vogue, CNN Supreme Court Reporter

(CNN) -- The Supreme Court dove into the issue of racial gerrymandering Monday as the justices reviewed a lower court opinion that struck down Virginia district maps as a violation of the Constitution.

The justices were considering 11 maps drawn by the legislature in 2011 that were successfully challenged by registered voters in each district, but several of them struggled at oral arguments with a threshold question, concerning whether the Republican-led House of Delegates had the "standing," or legal right, to bring the case to the Supreme Court. The issue could stop the justices from ever reaching the merits of the dispute, although it was unclear if a majority of the court had such concerns about the procedural issue.

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The case -- which has been tangled in the courts for years -- comes on the eve of the next census, after which new maps will be drawn.

The House had moved to intervene in the case after the state's attorney general -- a Democrat -- declined to do so. Virginia's solicitor general, Toby J. Heytens, told the justices on Monday that the House did not have the legal right to be in court. He told them they were being asked to "referee a dispute within the Virginia state government" and that Virginia law has been "clear since before the Civil War that the state's attorney general has the exclusive authority to make" the litigation decision.

"It isn't even the legislative branch" that's behind the challenge, Justice Ruth Bader Ginsburg said in apparent agreement with Heytens. "It's one house of the legislature," she said.

Justice Sonia Sotomayor seemed to agree, saying the redistricting plan "doesn't belong" solely to the House.

"At best, it belongs to the legislature as a whole or to the government, the people of Virginia," she said.

At one point, Justice Samuel Alito noted that Virginia law says the state's attorney general has the right to bring the suit. He said he would be "very uncomfortable" trying to decide whether, as a matter of Virginia law, anybody other than the attorney general can ever represent Virginia "or whether the House, under some circumstances, can also represent the commonwealth. "

But Alito also suggested that the House had been able to show the necessary concrete injury.

If the justices do reach the merits of the case, they will review a lower court opinion holding that "The Equal Protection Clause ensures that states do not engage in the offensive and demeaning assumption that voters of a particular race, because of their race, think alike, share the same political interests, and will prefer the same candidates at the polls," a panel of federal judges ruled last June.

It's the second time the justices have reviewed the case. Two terms ago, the justices upheld one district but asked the lower court to reconsider whether race was used improperly in the remaining 11.

Unlike the issue of partisan gerrymandering, the Supreme Court has settled on a standard to determine when states go too far in considering race. The court has said that if race is the predominate factor in drawing lines, then the use of race has to be narrowly tailored to advance a compelling governmental interest.

After fresh review and a new trial, the lower court held that the plaintiffs "have shown through telling direct and circumstantial evidence that race predominated over traditional districting factors."

Registered voters from each district, represented by election law expert Marc Elias, who served as the general counsel for Hillary Clinton's 2016 presidential campaign, argued that "African-American voters were moved in the challenged districts at a higher rate than white voters, Democratic voters, and the population as a whole -- and moved out at a lower rate than all these groups."

The consequence of the maps, Elias argued in court papers, was that African-American voters were crowded into the districts at issue so that their votes were diluted in surrounding areas.

The legislature sought to achieve an African-American voting age population of at least 55% in each district.

In briefs, Elias said the House of Delegates had imposed a "nonnegotiable" 55% black voting age population floor "across the board" despite the districts being "very different."

In striking the maps, the lower court held that the legislature "made no effort to determine whether the mechanical 55% racial threshold was required to comply with the VRA (Voting Rights Act), and instead arbitrarily applied the same racial mandate" to "vastly" dissimilar districts.

"The district court made extensive fact finding and followed the Supreme Court's instruction on how to deal with this to a 'T,' consistent with how the court has ruled in every racial gerrymander that has come before it this decade," said Allison Riggs, a staff attorney at the Southern Coalition for Social Justice who supports the challengers.

Justice Brett Kavanaugh, however, seemed to side with the House and suggested that others, such as the Virginia Legislative Black Caucus, had been consulted at the time.

"I'm wondering why 55% is so problematic here," he said. Kavanaugh also noted that the plan had been successfully approved -- or precleared -- by the Justice Department. Kavanaugh said that if the state had chosen a smaller percentage, it likely would have been "hammered" by some accusing it of "discriminating against African-American voters because you're not giving the voters a sufficient opportunity to elect the candidate of their choice."

A lawyer for the House of Delegates argued that the lines had been drawn utilizing traditional redistricting factors including compactness, contiguity and a respect for political subdivisions.

In addition, when the maps were drawn, Virginia was a covered jurisdiction under the Voting Rights Act that mandated the legislature draw maps that would not result in retrogression of a minority group's ability to elect its preferred candidate.

Paul Clement, a lawyer for the House, argued that legislators "widely agreed" that targeting a 55% African-American voting age population would best prevent retrogression. Clement said the Justice Department had precleared the map, which was used for the next two elections and was challenged only after a Democratic governor was sworn in.

Clement argues that the legislature is "walking the tightrope" between the Constitution, which restricts the consideration of race in the redistricting process, and the Voting Rights Act, which "often insists that districts be created precisely because of race."