Newly uncovered evidence shows that a Republican redistricting strategist played a significant role in the Trump administration's efforts to add a citizenship question to the census, undercutting the administration's argument that the question is needed to enforce the Voting Rights Act.

In a letter filed in federal court in New York on Thursday, lawyers from the ACLU wrote that new documents have emerged indicating that the late GOP strategist Thomas Hofeller conducted a 2015 study showing that asking about citizenship on the census would help Republicans and white populations in redistricting, while harming Democrats and Latino communities.

The redacted documents also allege that Hofeller first suggested the idea of reinstating the question to Trump transition officials. And they claims that the strategist helped orchestrate the question's addition and that Trump administration officials did not disclose his involvement, contradicting their sworn testimony.

This evidence is among the strongest evidence to date rebuking the Trump administration's arguments that it is only interested in asking about citizenship in order to help the Justice Department enforce the Voting Rights Act.

And it could throw a wrench in the case as it's being decided by the Supreme Court. Justices are currently weighing the citizenship question case, and are expected to issue their ruling by the end of June.

The ACLU filed a notice of the new evidence to the Supreme Court later Thursday, formally bringing it to the justices's attention.

Solicitor General Noel Francisco, who represents the administration, argued before the justices in April that asking the question will help with enforcing the voting law.

But the group of states - led by New York - as well the ACLU-led coalition of immigration groups and House Democrats claim that asking about citizenship on the 2020 census will lead to an inaccurate population count.

Census data is used to determine things like federal funding and the drawing of congressional districts - and asking about citizenship could cause non-citizens and immigrants to skip the question or the census altogether, the question's opponents argue.

The letter filed Thursday alleges that Hofeller had conducted the survey on adding a citizenship question for the Washington Free Beacon in 2015.

And it said that Hofeller wrote that the results of adding the question "would be advantageous to Republicans and Non-Hispanic Whites," "would clearly be a disadvantage for the Democrats," and would "provoke a high degree of resistance from Democrats and the major minority groups in the nation."

The document also alleges that A. Mark Neuman, an expert adviser to Commerce Secretary Wilbur Ross on census issues, said that the strategist was the "first person" to raise the possibility of adding the citizenship question to Trump transition officials,

Neuman said that Hofeller said that adding the question would "maximize[]" representation for the "Latino community," despite having evidence that it would actually harm districts with significant Hispanic populations.

The letter further states that Hofeller provided writing to Neuman, that in turn was included in a draft letter that Neuman gave to John Gore, a top DOJ official in the civil rights division.

"Nor did Neuman or Gore disclose that Dr. Hofeller ghostwrote a substantial part of the Neuman DOJ Letter setting forth the VRA rationale," the document reads.

"Thus, we now know that there is a direct line from Dr. Hofeller's advice that adding a citizenship question would advantage Republicans and non-Hispanic whites to the ultimate DOJ letter and its VRA rationale on which Secretary Ross relied: When Commerce officials began scrambling to develop a VRA rationale in August 2017, Dr. Hofeller helped craft the rationale, which was adopted wholesale in the Neuman DOJ Letter."

Gore sent a version of that letter that included Hofeller's reasoning to the Commerce Department, arguing that DOJ needed the citizenship question to help with Voting Rights Act enforcement.

And the documents filed Thursday claim that Gore's DOJ letter "bears striking similarities" to Hofeller's 2015 study on the question.

"The new evidence demonstrates a direct through-line from Dr. Hofeller's conclusion that adding a citizenship question would advantage Republican and non-Hispanic whites to DOJ's ultimate letter," the document reads. "The new evidence thus not only contradicts testimony in this case, but it shows that those who constructed the VRA rationale knew that adding a citizenship question would not benefit Latino voters, but rather would facilitate significantly reducing their political power."

This new evidence was uncovered as part of a separate Common Cause lawsuit over partisan gerrymandering in North Carolina.

Judge Jesse Furman, who oversaw the original lawsuit, has ordered the administration to respond to the ACLU's filings by Monday and for all parties to appear in a hearing next Wednesday.

And he has given the government until 10 a.m. on Friday to submit any objections to the unredacted versions of the ACLU filings being made public.

This story was updated at 5:18 p.m.

May 30 2019 Letter to Judge Jesse Furman