A next potential front in the redistricting war could involve who is counted for state legislative districts.
For decades, mapmakers have generally drawn the districts that state lawmakers represent based on the total number of people living in an area. But Republican officials in some states have called for using a narrower population: only "eligible voters."
Some advocates of this form of redistricting have interpreted it to mean leaving out non-U.S. citizen adults and all children. Only adult citizens would count, including those who, in some states, are not eligible to vote because of a felony conviction or their mental incapacity.
Such a change would likely lead to a transfer of political influence — away from urban areas that are younger and more racially diverse, and toward rural areas that are older and whiter.
In 2016, the Supreme Court ruled that a state is allowed to draw legislative districts based on its total population. "As the Framers of the Constitution and the Fourteenth Amendment comprehended, representatives serve all residents, not just those eligible or registered to vote," wrote the late Justice Ruth Bader Ginsburg in the court's unanimous opinion after a local GOP official and another Texas voter challenged a state Senate map.
But the high court stopped short of ruling on the legality of state legislative mapmaking based only on adult citizens, with Justice Samuel Alito authoring a concurring opinion calling it "an important and sensitive question" the justices could consider if such a plan were brought to the court.
A decade later, Republican officials in some states have filed lawsuits that could end up forcing the Census Bureau to release the information that linedrawers would need to create such a redistricting plan — census block-level data about people's U.S. citizenship status.
Missouri, the latest GOP-led state to sue, would be primed to use that data after voters in 2020 approved new redistricting requirements in the state's constitution.
Still, any state wading into these uncharted redistricting waters would face both legal and practical hurdles, including whether the bureau can produce reliable block-level citizenship data in time for the next round of scheduled redistricting, after the 2030 census.
And while Republicans would be more likely to benefit than Democrats, the partisan gains from redistricting based on adult citizens may not be enough to change the balance of power in many state legislatures, a study suggests.
How the GOP push to alter the census connects with adult citizen-based districts
The push to change who's counted in state legislative districts comes amid Republican efforts to exclude some or all noncitizens living in the states from certain or all census tallies.
To produce a narrower population count, the bureau would need to add to census forms a question asking about U.S. citizenship and/or immigration status — or resurrect a citizenship data project from the first Trump administration involving government records.
Such a question or project would also unlock adult citizen-based redistricting in Missouri, according to Nick Stephanopoulos, a professor specializing in election law at Harvard Law School.
"To do redistricting, you need really granular data on where people or citizens or adult citizens are located," Stephanopoulos adds.
Catherine Hanaway, Missouri's Republican attorney general, did not agree to be interviewed or respond to written questions.
But in the state's legal complaint against the bureau, Missouri claims that including residents without legal status and those with nonimmigrant visas in the census "hopelessly skews" legislative redistricting, noting that the state's constitution requires those districts to be drawn on the basis of "one person, one vote."
"Indeed, it is impossible to comply with the 'one person, one vote' rule," the complaint adds, "when Missouri must rely on census data altered by the inclusion of illegal aliens and temporary visa holders," such as international college students who live in the United States.
A few months before Missouri voters approved that rule in 2020, the state's solicitor general at the time — D. John Sauer, who is now the Trump administration's top Supreme Court lawyer — told a judge that the state government interpreted it to mean that "the criteria is based on the number of actual eligible voters in a relevant district as opposed to an absolute population."
Republicans would likely benefit, but not in many states, a study suggests
The first Trump administration failed in its attempt to add a citizenship question to the 2020 census, but the effort led to the release of a 2015 report by the late Thomas Hofeller, a Republican redistricting strategist.
In the document, Hofeller wrote that redrawing state legislative districts based on adult citizens "would be advantageous to Republicans and Non-Hispanic Whites."
Stephanopoulos of Harvard Law School, however, doesn't completely agree with Hofeller's conclusion.
"Tom Hofeller's memo was right about the consequences for minority voters versus white voters, but it largely overstated the effects with respect to partisanship," says Stephanopoulos, who co-authored a 2021 academic study involving simulated redistricting plans for Arizona, California, Florida, Georgia, Idaho, Illinois, Nevada, New York, Texas and Utah.
Adult citizen-based redistricting, the study found, would reduce the number of legislative districts in which Black or Latino voters have an opportunity to elect their preferred candidate in places where voting is racially polarized — a key protection against racial discrimination under the Voting Rights Act of 1965. The most notable drops would likely be in Arizona, Florida, New York and Texas.
In most states, however, this method of mapmaking is not likely to give Republicans an edge in control of state legislatures, according to this research.
The exceptions would be Florida and Texas, where Republicans have controlled the state legislatures for decades. With adult citizen-based redistricting, "both of those states' lower houses would be comfortably Republican, not close to flipping to the Democrats," Stephanopoulos and his co-author, Jowei Chen at the University of Michigan, wrote in their California Law Review article.
Where the legal fight over the census and redistricting stands
Still, a lack of a major partisan benefit in Missouri and other states may not deter Republicans from trying out this kind of redistricting.
"I think what's going on here is this kind of ideological push to adopt certain electoral reforms," Stephanopoulos says. "There's no reason to think this is really going to benefit Republicans in partisan terms, but they're still pushing for it. It's become adopted as part of the current platform of Republican thinking about elections — that we ought to have apportionment based on equal citizens, not based on equal persons."
In a 2019 executive order from his first term, President Trump made clear his thinking about the need for citizenship data that would allow states to "design State and local legislative districts based on the population of voter-eligible citizens."
So far, the current Trump administration has not directly addressed the topic in public.
But hours after his second swearing-in as president, Trump revoked a Biden-era executive order that had rescinded his 2019 order on citizenship data from the census.
Trump and other Republicans have also renewed their calls for removing some or all noncitizens from the set of census numbers used to determine each state's share of congressional seats and Electoral College votes, even though the 14th Amendment says those apportionment counts must include the "whole number of persons in each state."
In February, the Trump administration proposed using a citizenship question for this year's field test of the 2030 census. And in a recent court filing for a lawsuit against the bureau by Louisiana, Kansas, Ohio and West Virginia, the administration said its upcoming release of proposed rules for who should be counted "may result in the dismissal of this case, or narrow the issues before the Court," signaling it may soon formally adopt the position that the bureau should not tally up some or all noncitizens.
In the meantime, some immigrant advocacy and civil rights organizations are questioning whether the administration's attorneys will "vigorously" defend the bureau in the state cases.
The NAACP and its Missouri chapter, represented by the Democratic-aligned firm Elias Law Group, are among the organizations that have asked a federal judge to allow them to step in as intervenors in Missouri's lawsuit. Their Black members in cities such as St. Louis and Kansas City, Mo., they argue, are at risk of having their votes for the Missouri General Assembly diluted because the state is trying to force redistricting that would "exclude certain categories of immigrants, skewing the results against Missouri's large urban areas—where immigrants are more likely to reside—and in favor of more rural areas."
Edited by Benjamin Swasey
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