On Tuesday morning the Supreme Court heard Evenwel v. Abbott, the most important voting rights case since the Court’s conservative majority gutted the Voting Rights Act (VRA) in 2013. The same people who successfully challenged the VRA are now targeting the historic principle of “one person, one vote.”

They want legislative lines to be drawn based on eligible or registered voters instead of total population, thus not counting children, immigrants (documented and undocumented), prisoners, and other nonvoters. If that happened, districts would become older, whiter, more rural and more conservative, with 55 percent of Latinos, 45 percent of Asian Americans and 30 percent of African Americans excluded from political representation. The same communities most harmed by the gutting of the VRA would see their political influence further diminished.

The court appeared divided on how to proceed. Chief Justice John Roberts, who authored the opinion dismantling a key part of the VRA, expressed sympathy with the plaintiff’s argument. “Well, it is called the one person, one vote,” Roberts said. “That seems to be designed to protect voters.”

Justice Sonia Sotomayor responded that states have not just a “voting interest” but “also a representation interest.” She elaborated: “A state has to be able to say—I think just as the federal government did—the legislature is protecting not just voters; it’s protecting its citizens—or noncitizens. The people who live there.”

“What we actually want,” Justice Stephen Breyer said, “is the kind of democracy where people, whether they choose to vote or whether they don’t choose to vote, are going to receive a proportionate representation in Congress.”

Justice Ruth Bader Ginsburg, in an exchange with plaintiff lawyer William Consovoy, noted that under his interpretation of the law women would have been excluded from political representation before the passage of the 19th Amendment in 1920.

ginsburg: Is it your view that what the Fourteenth Amendment means is that in all the years between 1868 and 1920, it was wrong for the states to include, for these purposes, women? They were not eligible voters.

consovoy: There is no question that was a problem. It was an issue in the ’60s with minorities as well who were disenfranchised. The Court in [Reynolds v. Sims] at the time was doing more than one thing at once.

ginsburg: But you’re saying that was wrong. In your interpretation of the Fourteenth Amendment from 1869 till 1920, the State should not have been counting women for purposes of determining representation in the State legislature.

The swing vote on so many of these cases, Justice Anthony Kennedy, seemed to be searching for a middle ground between the plaintiff’s claim of “voter equality” and the longstanding principle of “population equality.”

“Why can’t you have both?” he asked.

Texas Solicitor General Scott Keller responded that any change to “one person, one vote” would “inevitably have to disregard many other traditional redistricting factors, like compactness, continuity, keeping communities together. And that would be the opposite of what the Court has said that States have in this context, which is the leeway to structure their elections as part of the core function of their sovereignty.”

“That sounds highly probable to me,” Kennedy responded.

Unlike the VRA case in 2013, the civil-rights groups defending “one person, one vote” sounded confident after the oral arguments. Nina Perales of the Mexican-American Legal Defense Fund said she was “very heartened” by the questions the justices asked.

But as I wrote recently for The Nation, “that the Court is even hearing the Evenwel case is a major victory for the plaintiffs, regardless of the final outcome.” The “one person, one vote doctrine” has been settled law for more than 50 years and there is no pressing reason to reexamine it now. The Evenwel case demonstrates how opponents of voting rights will keep finding new ways to undermine the power of an increasingly diverse electorate and won’t stop anytime soon.