Newly surfaced documents reveal a senior Republican strategist who specialized in gerrymandering was secretly behind the Trump administration’s efforts to add a citizenship question to the 2020 census. When the strategist, Thomas Hofeller, died last August, he left behind a computer hard drive full of his notes and records. Hofeller’s estranged daughter found among the documents a 2015 study that concluded that adding the citizenship question to the census “would be advantageous to Republicans and non-Hispanic whites” and “would clearly be a disadvantage to the Democrats.” Census officials have estimated 6.5 million people will not respond to the census if the citizenship question is added. This undercount could affect everything from the redrawing of congressional maps to the allocation of federal funding. In a court filing Thursday, plaintiffs challenging the citizenship question accuse two Trump administration officials of falsely testifying under oath about the Justice Department’s motivations for altering the census. The Supreme Court is set to rule within weeks on whether Commerce Secretary Wilbur Ross had the authority to add the citizenship question to the census.