An effort by conservatives to move states away from drawing districts using total population — with a lawsuit civil rights advocates said was designed to dilute the political power of minorities — seemed all but dead a year ago, after the Supreme Court ruled 8-0 against their argument.

However, should the Trump Justice Department get its way in a new push to include a citizenship question on the 2020 census, it could breathe new life into the effort. The result could be that some states draw their legislative districts in ways that reduce the voting power of minority communities and boost the power of white ones

As first reported by ProPublica, the Justice Department in a letter last month asked the Census Bureau to include a question about citizenship on its questionnaire. Civil rights groups, social scientists and even Census Bureau officials themselves have said that doing so threatens to depress census participation in immigrant communities. Undercounting those populations will bring about a host of repercussions, given the various uses of census data.

But the report also caught the eye of Ed Blum, a conservative legal activist who in 2014 spearheaded a case seeking to end the use of census total population data to draw state legislative districts. The lawsuit, Evenwel v. Abbott, asked the court to invalidate state legislative maps drawn based on total population. The challengers argued that gave too much weight to areas with large numbers of non-citizens.

The Supreme Court unanimously rejected that argument in its 2016 decision that reaffirmed the use of total population, which is a how a vast majority of states draw their districts.

But the new push to measure citizenship with the decennial census could help Blum and others overcome one of the deficiencies in their original case. Critics raised concerns that the proposal in Evenwel to use data other than total population in redistricting didn’t take into account the absence of reliable citizenship data. As political scientists and former Census Bureau officials argued in legal briefs in the case, the study the government uses to measure citizenship, the American Community Survey, was not designed for redistricting purposes.

When asked by TPM about the new push to measure citizenship via the census, Blum pointed to those briefs. If those social scientists are “asserting that the American Community Survey is not in-depth enough to get a true reading of who is a U.S. citizen and who is not,” Blum said, “then asking that question makes perfect sense.”

Blum said he was unaware that the DOJ was sending a letter requesting the question be added.

Notably, Texas, in its legal briefs defending its district maps at the time, said that it should be allowed to use other metrics, beyond total population, as long as its choice “is not irrational or made for an impermissible purpose.” The Obama administration, which otherwise sided with the Texas in the case, pointedly asked the court to not weigh in on Texas’ claim to have that sort of flexibility — though many legal experts have thought such flexibility could exist given a 1966 Supreme Court ruling allowing Hawaii to exclude its military population from its redistricting metric.

The Supreme Court’s Evenwel opinion said that the justices “need not and do not resolve” the question of whether Texas could draw districts based on voting age citizens, rather than total population. But Justices Samuel Alito and Clarence Thomas went a step farther in their concurrences, with Thomas arguing states should have the choice, and Alito calling it an “important and sensitive”question that will need to be resolved by another legal challenge.

Drawing legislative districts so that they equalize according to the number of legal citizens a district has instead of its total population would have huge implications for the political power of areas with a relatively high non-citizen populations, including immigrant communities. An analysis by Andrew Beveridge, a sociologist and demographics expert at CUNY, said that using citizen voting age instead of total population would result in a shift in voting power that would “substantially favor increasing the number of Republican-dominated districts.”

Beveridge told TPM his immediate reaction when he saw the reports about the Justice Department pushing a census citizenship question was, “Well, I think they’ll try Evenwel again.”

“But I don’t think they’ll win,” he added.

For the issue to bubble up again, a few more things would have to fall in to place for conservatives. First, the Census Bureau would have decide whether to grant the Justice Department’s citizenship question request, which is coming incredibly late in the planning process and as the bureau is facing an assortment of other hurdles in implementing an accurate count. Then, a state would need to choose to use a new metric that drew on the 2020 census’ citizenship data to draw its state legislative districts.

“I certainly think that there is a lot of concern that there will be efforts to lobby states to say, ‘You should take advantage of this opening in Evenwel to perhaps just use citizens and draw districts on that basis,'” Michael Li, senior counsel for the Brennan Center’s Democracy Program. “That’s something that the data hasn’t existed, but if it did, you could arguably do that, and there’s going to be an argument that states should do that.”

If they did, then the issue would have to go back to the courts, which Blum said was a given.

“If a state or jurisdiction elects to use a metric other than total population for the next round of redistricting, then I am sure there will be a lawsuit challenging that plan,” Blum said. “And it’s likely the Supreme Court would then be compelled to clarify its earlier indecision.”

It’s an extremely long game, but one that would be “holy grail” for the right, as Beveridge put it.

“That’s a pretty big change. It would mean significantly changing the legislature of every single state in the country,” Li said. “This is a world where people are trying a bunch of new things, trying to figure out how you can eke an additional advantage.”

Yet among the opponents of the Evenwel lawsuit is a deep skepticism that this hypothetical manuever would be successful where that case fell short.

“I don’t know of any time in history that an 8-0 decision was revisited so soon,” said Thomas Saenz, the president and general counsel of Mexican American Legal Defense and Educational Fund, which opposed Blum in the Evenwel case.