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 white Republicans.

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,’ ” and that Trump administration officials purposely obscured Hofeller’s role in court proceedings, lawyers for plaintiffs challenging the question wrote in a letter to U.S. District Judge Jesse M. Furman. Furman was one of three federal judges who ruled against the question this year.

The letter drew on new information discovered on hard drives belonging to Hofeller, which were found accidentally by Hofeller’s 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 “advantageous to Republicans and Non-Hispanic Whites” in redistricting, and then pushed the idea with the Trump administration in 2017, according to the letter to Furman.