Supreme Court alerted to 'new evidence' on Census citizenship question Opponents of citizenship question on 2020 census say they have new evidence.

Opponents of the Trump administration's plan to ask about citizenship on the 2020 census have alerted the U.S. Supreme Court of what they call "smoking gun" evidence that government officials lied in sworn testimony about their rationale for adding the question.

The submission, a letter Thursday from ACLU attorney Dale Ho, who argued the case before the court last month, comes as the justices have been deliberating on the case and expected to hand down their decision within weeks.

"The new evidence reveals that Dr. Thomas Hofeller, a longtime redistricting specialist, 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,'" Ho writes.

"Petitioners [the Commerce Department] obscured his role through affirmative misrepresentations," he said.

The evidence could call into question the administration's claims that the citizenship question was specifically requested by the Justice Department to aid enforcement of the Voting Rights Act. Government officials have denied allegations of bald politics or racial discrimination as true motives.

News of Hofeller's role was first reported by the New York Times.

Hofeller, well-known in Republican circles as a tactician, had extensively studied the value of citizenship data in gerrymandering. He died last year.

"The new evidence 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," attorney John Freedman wrote in a filing with U.S. District Court of the Southern District of New York, which first heard the case.

A Justice Department spokeswoman said Hofeller’s work played no role in the administration’s decision to pursue a citizenship question. “These eleventh-hour allegations by the plaintiffs, including an accusation of dishonesty against a senior Department of Justice official, are false,” the spokeswoman said.

“These unfounded allegations are an unfortunate last-ditch effort to derail the Supreme Court’s consideration of this case,” she said, noting the Department would formally respond to the court next week.

Three lower federal courts found that Commerce Secretary Wilbur Ross acted illegally – in an "arbitrary and capricious" manner -- circumventing the Administrative Procedures Act, which requires federal agencies to carefully study all relevant evidence and facts pertaining to a problem before implementing a new policy.

One federal judge in Maryland also said Ross violated the Constitution "by unreasonably compromising the distributive accuracy of the Census."

During arguments at the Supreme Court last month, the liberal justices clashed with Solicitor General Noel Francisco over the fairness and necessity of the citizenship question, but a majority on the bench seemed inclined to accept the Trump administration's argument of broad executive discretion in conducting the census.

"This boils down to whether the secretary's judgment here is a reasonable one," said Francisco at the time.

Justice Brett Kavanaugh pointed out that several major countries ask a citizenship question on their census, which is a recommendation by the United Nations. Chief Justice John Roberts signaled noted that there are already other demographic questions on the Census.

"The administration has a great deal of discretion to make policy choices, but the law is clear that they can’t lie about their reasons or manufacture justifications that conceal their true motivations," said ABC News Supreme Court analyst Kate Shaw. "The big question here is whether the Court will consider this new evidence at such a late hour. It would be highly unusual for it to do so, but a lot of things about this case are unusual."

The justices could ask for new briefs from both sides on the issue or could delay the decision.

How the justices rule will impact the decennial count which determines how congressional seats are apportioned, how many electoral votes each state receives in a presidential election and how billions in taxpayer dollars are distributed on a per capita basis.