In 2017, as he was deposed under oath in a federal lawsuit challenging gerrymandered North Carolina congressional district maps, he was asked about directives Republicans had given him.
Hofeller had conducted a study in 2015 which found that adding such a question would make it possible to draw district boundaries that "would be advantageous to Republicans and non-Hispanic whites."
[2] The New York Times described the files as "the most explicit evidence to date that the Trump administration added the question to the 2020 United States Census to advance Republican Party interests.
"[2] In May 2019, the plaintiffs suing over the 2020 United States Census citizenship question cited the 2015 Hofeller analysis and other documents in a motion for sanctions, saying "many striking similarities" existed between the unpublished Hofeller analysis and the United States Department of Commerce's decision to seek a citizenship question on the Census.
[2] The federal government, in response, said that the Hofeller study "played no role in the department's December 2017 request" for a citizenship question on the Census.
[2] In June 2019, the United States Court of Appeals for the Fourth Circuit, citing the Hofeller document, remanded the case to the U.S. district court to determine whether the Trump administration's stated rationale for adding a citizenship question to the 2020 census was in fact a pretext for a discriminatory purpose (the dilution of voting power of Hispanic voters in order to advantage Republicans and non-Hispanic whites).
David Daley wrote that the files "...mostly pertain to Hofeller’s work in North Carolina, where he drew—and defended in court—the state’s legislative and congressional maps multiple times, after judges ruled them to be either unconstitutionally partisan or racial gerrymanders.
Mark Joseph Stern wrote in Slate, "The court had unprecedented access to the gerrymandering process thanks to the Hofeller files..."[9] The court cited from Hofeller's files that "metadata on maps of state legislative districts showed they were almost completely drawn months before Republican legislative leaders publicly adopted the standards for drawing them."
[11] In November 2019, a court ruled that Hofeller's files were no longer considered confidential as they address political activities in other states, affecting redistricting and the national census, and could be used in other suspected cases of gerrymandering.