WASHINGTON – Just weeks before the Supreme Court is expected to rule on whether the Trump administration can add a citizenship question to the 2020 Census, new evidence emerged Thursday suggesting the question was crafted specifically to give an electoral advantage to Republicans and whites.

Thomas Hofeller, center, attends a House Government and Oversight Census Subcommittee meeting regarding the use of statistical sampling in the 2000 census in 1998. The Washington Post/Ray Lustig

The evidence was found in the files of the prominent Republican redistricting strategist Thomas Hofeller after his death in August. It reveals that Hofeller “played a significant role in orchestrating the addition of the citizenship question to the 2020 Decennial Census in order to create a structural electoral advantage for, in his own words, ‘Republicans and Non-Hispanic Whites,’ ” plaintiffs’ lawyers challenging the question wrote in a letter Thursday morning to U.S. District Judge Jesse Furman, one of three federal judges who ruled against the question this year. The lawyers also argued that Trump administration officials purposely obscured Hofeller’s role in court proceedings.

The letter drew on new information discovered on hard drives belonging to Hofeller, which were found inadvertently by his estranged daughter. Stephanie Hofeller Lizon then shared them with the organization Common Cause for a gerrymandering lawsuit it is pursuing in North Carolina.

The files show that Hofeller concluded in a 2015 study that adding a citizenship question to the 2020 Census “would clearly be a disadvantage to the Democrats” and benefit white Republicans in redistricting. Hofeller then pushed the idea with the Trump administration in 2017, according to the lawyers’ letter to Furman.

The evidence, first reported by the New York Times, contradicts sworn testimony by Commerce Secretary Wilbur Ross’ expert adviser A. Mark Neuman and senior Justice Department official John Gore, as well as other testimony by defendants, the letter said.

A Justice Department official said the agency was unaware of the allegations in the motion but will file a response. Officials at the Commerce Department did not respond to questions about the new information.

The American Civil Liberties Union filed a motion in district court Thursday morning for “sanctions and any other relief the court deems appropriate, because of apparently untruthful testimony” by Trump administration officials in the earlier trials, said Dale Ho, who argued the case at the Supreme Court on behalf of the ACLU.

It is unclear how the information might affect deliberations at the Supreme Court. The ACLU filed a letter with the court Thursday afternoon to “respectfully inform” it of the motion filed in the New York district court and that a hearing was scheduled for next week.

The letter repeated the charge contained in the letter to Furman that Hofeller played a significant role in adding the citizenship question to the 2020 Census to give white Republicans a redistricting advantage and that the Trump administration “obscured his role through affirmative misrepresentations.”

Ho’s letter did not ask the court to take action, but drew its attention to the new motion and that the hearing would be Wednesday.

“Witnesses misrepresented the origin and purpose of their effort to add a citizenship question to the census,” Ho said in a statement accompanying release of the letter. “Their goal was not to protect voting rights, but to dilute the voting power of minority communities. We look forward to Wednesday’s hearing and will keep the Supreme Court aware of any further developments.”

The Supreme Court heard the case April 23. Evidence in the case concluded with oral arguments that day, and it appeared that the conservative majority seemed inclined to agree with the government that the decision to add the question was within the authority of the commerce secretary.

If the court followed normal procedure, it voted that week on the outcome of the case, and the justices are now writing the opinion.

The ACLU also asked the district court to allow previously redacted testimony from Neuman to be made public. On Thursday, Furman ordered that the government must provide a response by 10 a.m. Friday and called a hearing on the matter for Wednesday.

The new information indicates that blueprints for adding a citizenship question to the 2020 Census predated the Trump administration, but Donald Trump’s election allowed them to become a reality, Ho said.

“It just shows that there was a long-standing plan to weaponize the census to dilute minority voting power to try to forestall the electoral effects of the demographic changes that this country is undergoing,” he said.

Ho said sanctions could include fines imposed on witnesses or the government, a reopening of the case or an amendment of the final judgment to account for new evidence.

The population count from the decennial census is used to allocate $800 billion a year in federal funding and determine congressional representation and redistricting. Opponents of the citizenship question have argued that it will suppress response to the survey among immigrant communities, resulting in an undercount in the areas where they live.

Hofeller’s files also reveal that in August 2017 he helped ghostwrite a draft Justice Department letter to the Commerce Department requesting a citizenship question and coming up with a rationale – to help enforce the Voting Rights Act, the plaintiffs’ lawyers said. He then gave this letter to Gore, the principal deputy assistant attorney general, in October 2017, they said.

The genesis of that request and the rationale behind it were key questions in trials challenging the question. Ross initially had told Congress that the request was initiated by the Justice Department in a December 2017 letter, but administration documents released in the case later indicated that it came at Ross’s urging, starting months earlier. Census and voting rights experts have said the question is not needed to enforce the Voting Rights Act.

The Justice Department letter “bears striking similarities to Dr. Hofeller’s 2015 study, stating that a citizenship question on the Census was essential to advantaging Republicans and white voters,” the letter to Furman said. It added: “Based on this new evidence, it appears that both Neuman and Gore falsely testified about the genesis of DOJ’s request to Commerce in ways that obscured the pretextual character of the request.”

Critics of the question blasted the administration after the news broke.

“Republican political operatives plainly want to deny communities of color the health care, education and other services they need in order to consolidate GOP power and a whiter electorate,” said Vanita Gupta, president and CEO of the Leadership Conference on Civil and Human Rights. “We call on Congress to hold Trump administration officials – including Secretary Ross – accountable now and not to wait until after the Supreme Court ruling to do so.”

Terri Ann Lowenthal, a former staff director of the House census oversight subcommittee, said the new information undercut the bureau’s years of work to plan a nonpartisan count.

“Revelations that this administration threw a grenade into that process in order to achieve partisan goals must be a gut-punch to every career Census employee whose goal is to earn the public’s trust and confidence in the 2020 Census,” she said.

In April the high court’s five conservatives seemed to lean toward allowing the question, citing the Voting Rights Act rationale and focusing not on Ross’ motivations, but rather on whether he was simply using the power he was authorized to exercise.

The court’s liberal justices were skeptical. Justice Elena Kagan said Ross seemed to be “shopping for a need,” trying unsuccessfully to get Justice and Homeland Security officials to request the question before finally getting the Justice Department to agree.

“You can’t read this record without sensing that this – this need is a contrived one,” she said. “There have been lots of assistant attorneys general in the [Justice Department’s] Civil Rights Division that have never made a plea for this kind of data.”

Justice Brett Kavanaugh wondered if courts should be making the decision. “The statute that Congress has passed gives huge discretion to the secretary [in] how to fill out the form, what to put on the form,” he said.

If Congress is unhappy with the secretary’s decision, “why doesn’t Congress prohibit the asking of a citizenship question in the same way that Congress has explicitly provided that no one can be compelled to provide religious information?” Kavanaugh asked.

Since taking control of the House in January, some Democrats are seeking to do exactly that. This spring, Congressman Jose Serrano, D-N.Y., chairman of the Commerce, Justice and Science appropriations subcommittee, included as part of the appropriations bill a stipulation that no funding could go toward incorporating any question onto the census that was not included in last year’s end-to-end testing (which did not include the citizenship question). The full committee voted last week in favor of the bill, which will next be considered on the House floor.

But for now the Republican-led Senate seems unlikely to pass a bill with similar wording, and the Trump administration would have the discretion to veto such a bill.

Democratic lawmakers have accused the Trump administration of stymying their efforts to investigate the decision to add the question.

In March Democrats on the House Oversight and Reform Committee grilled Ross about it for six and a half hours, with several asking if he had lied under oath and one demanding his resignation.

The committee voted in early April to authorize committee Chairman Elijah Cummings, D-Md., to issue subpoenas for a deposition of Gore, Ross, and Attorney General William Barr for documents related to the decision.

But the Justice Department said it would not comply with a congressional subpoena for Gore to testify about the question, and the Trump administration has vowed to stonewall all House subpoenas.