The campaigns of several Democratic presidential contenders told TPM in recent days that their candidates, if elected, would seek to block the federal government from assisting states in an anti-immigrant, pro-GOP redistricting overhaul.

The GOP-envisioned overhaul would change redistricting by abandoning the use of total population to draw electoral maps in favor of a metric that excludes noncitizens.

Doing so “would be advantageous to Republicans and Non-Hispanic Whites,” a now-deceased GOP gerrymandering consultant wrote in 2015.

The redistricting overhaul appeared to be one of the goals of adding a citizenship question to the 2020 census. The Trump administration has backed down from that fight, having been blocked by the Supreme Court. However, the federal government is still collecting the citizenship data using existing records held by various agencies, and it plans to offer it to states to use for redistricting in 2021.

A number of Democratic campaigns for president — including those of Sen. Elizabeth Warren (MA), former HUD Secretary Julian Castro and Sen. Cory Booker (NJ) — told TPM they opposed sharing the citizenship data and that they’d seek to block it if elected. Booker has introduced legislation to block citizenship data from being offered to states for redistricting, though that bill stands no chance of becoming law given the GOP Senate and White House.

The full list of candidates and their responses is at the bottom of the post.

It’s unclear how successful an administrative move by a Democratic president to block states from getting citizenship data would be.

In theory, he or she could direct the Census Bureau not to include citizenship data on the redistricting file it provides to states. The Census Bureau is required by law to release the file by April 1, 2021. Michael McDonald, a professor who specializes in election administration, equated the hypothetical move to President George W. Bush’s successful effort to stop the Census Bureau from making statistical adjustments to census data to make up for undercounted populations.

A Democratic administration could suppress release of the citizenship data in Feb. 2021, much like the Bush administration did in 2001 to stop release of decennial census data statistically adjusted for undercounted populations — Michael McDonald (@ElectProject) July 11, 2019

However, perhaps learning the lessons of the citizenship question debacle — where the government was blocked from adding the question due to a violation of administrative law — the Trump administration has been careful and deliberative in laying the groundwork for giving citizenship redistricting data to states.

The administration first indicated in a regulatory filing it was considering offering the data the back in July 2018 and has sought the weigh-in of stakeholders, i.e. legislative map drawers. There have been additional indications it was considering the change in subsequent notices and a final announcement of it is expected in the weeks to come.

An attempt by a Democratic president to block the Census Bureau from providing the data in early 2021 may invite a legal challenge, given how quickly he or she would have to work to reverse the federal government’s meticulously-laid plans to share the data.

Nonetheless, the stakes are incredibly high for Democrats as they head into a post-2020 census redistricting cycle where states will already likely be pushing partisan gerrymandering to the extreme, given a Supreme Court decision green-lighting the practice.

Excluding noncitizens from redistricting is essentially a type of gerrymandering on steroids. If states equalize districts by number of citizens rather than total population, areas with large Latino communities or other immigrant populations will see the number of legislative representatives they receive reduced, while the representation of white, rural and thus Republican areas increases.

Additionally, Attorney General Bill Barr hinted that the citizenship data could be used for congressional apportionment — the process by which the number of U.S. House seats are doled out among states — if a lawsuit seeking to exclude undocumented immigrants from that count is successful.

Here are the Democratic 2020 candidates who say they’d oppose the federal government offering states the citizenship data for redistricting:

Cory Booker

After Booker unveiled legislation to block the Census Bureau from sharing the data, his presidential campaign confirmed that Booker, if elected President, would direct his agencies to not include the data on the Census Bureau’s redistricting file.

Julian Castro

“As President, Sec. Castro would direct the Census Bureau not to include the citizenship data gathered in the redistricting data file,” his campaign said in a statement to TPM.

Bill de Blasio

“The mayor believes that that information should not be collected and wouldn’t use it in any form,” a campaign representative said.

John Hickenlooper

Per the former Colorado governor’s presidential campaign: “As president, Hickenlooper would direct the Census Bureau to not include any citizenship data collected at Trump’s direction on the redistricting file that is given to states in 2021. He would follow the Constitution. The Constitution clearly calls for congressional districts to be based on the total population. The courts saw through the Trump Administration’s attempt to include a citizenship question on the census without any proper justification.”

Seth Moulton

A representative for Moulton’s campaign told TPM that the Massachusetts U.S. House member “does not believe this should be policy because we should be counting all persons to ensure accurate and democratic representation.”

Beto O’Rourke

“If elected, President O’Rourke would direct the Census Bureau to not include the citizenship data on the redistricting file that is given to states in 2021,” a campaign spokeswoman for the former Texas representative said.

Tim Ryan

Ryan’s campaign told TPM that the candidate would oppose putting citizenship data on the redistricting file. Its statement focused on the use of citizenship data for apportionment: “While Citizens are responsible for choosing representatives, representatives are responsible for making decisions that affect all people living in a district. Apportionment is meant to reflect how many people, not citizens, are living in a particular place and citizenship as a status should not play a role in determining how many members a state should get. ”

Elizabeth Warren

A campaign representative said that “as President, Elizabeth would not pass on discriminatory citizenship data to states.”

Marianne Williamson

Per her campaign: “Donald Trump is looking for another way to use government data to profile segments of our population to further his personal political agenda. A Williamson Administration would not gather or use census citizenship data for redistricting purposes.”

Andrew Yang

“The Constitution clearly sets total population, not number of citizens, as the criteria for Congressional apportionment. There’s no reason to include the citizenship data on any materials related to that determination,” Yang said in a statement provided by his campaign. His campaign confirmed that he is also opposed including citizenship data on materials for legislative redistricting, upon a request for clarification from TPM.

Sen. Kristen Gillibrand (D-NY)’s presidential campaign sent TPM a statement expressing opposition to the citizenship question on the census. But the campaign have not responded to requests for clarification on how candidates would address the move to share citizenship data collected from existing records.

The remaining 2020 Democratic presidential campaigns did not respond to TPM’s inquiry.

Updated: This story has been updated to include the responses from the campaigns of former Rep. Beto O’Rourke (D-TX), Rep Tim Ryan’s (D-OH) and New York City Mayor Bill de Blasio.