Washington (CNN) Challengers to the Trump administration's decision to add a citizenship question to the 2020 census informed the Supreme Court on Thursday that they believe they have "new evidence" that the move was politically motivated.

They point to a newly disclosed 2015 study written by Dr. Thomas Hofeller, a Republican redistricting expert, who wrote that using "citizen voting age" population as the redistricting population base would be "advantageous to Republicans and Non-Hispanic Whites."

The challengers, including groups such as the American Civil Liberties Union and Common Cause, say the new information shows Hofeller played a more significant role in the decision to add the citizenship question than has been disclosed and that his study reveals the true motive behind the administration's decision to add the question.

Separately in a letter to District Judge Jesse M. Furman on Thursday, the challengers say the evidence bolsters their argument that while the administration contends the question was added to better comply with federal voting laws, the real reason was to intimidate Hispanic households from being counted.

"The new evidence thus not only contradicts testimony in this case, but it shows that those who constructed the VRA (Voting Rights Act) rationale knew that adding a citizenship question would not benefit Latino voters, but rather would facilitate significantly reducing their political power," the letter to the judge reads.

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