WASHINGTON — When a House committee sued senior Trump administration officials this past week over their refusal to turn over details of the administration’s failed attempt to add a citizenship question to the 2020 census, it might have seemed a post-mortem to an issue long settled.
But five months after the Supreme Court blocked the question, a steady trickle of new disclosures in the case this past month has sharpened questions about whether Republican Party politics drove the effort to add the question to the head count — and whether the Trump administration tried to conceal that in court.
The disclosures, in a House of Representatives inquiry and a New York lawsuit, bolster existing evidence that a Republican political strategist, Thomas B. Hofeller, played at least an indirect role in crafting a legal rationale for adding the question to the census. They also indicate that a senior Census Bureau official and friend of Mr. Hofeller, Christa Jones, helped draft an explanation of that rationale, apparently for publication had the question been approved.
Those developments could help efforts by critics to definitively pin down how the citizenship question became a Trump administration priority and whether Justice Department officials should be sanctioned for withholding evidence relating to it. Federal judges are hearing demands by the House Oversight and Reform Committee and by plaintiffs in the census lawsuit filed in New York to unseal a trove of census-related documents that the administration has refused to turn over.
The latest disclosures tend to support their claim that the administration’s stated reason for adding the question — to help enforce the Voting Rights Act — was a pretext for a scheme to boost Republican political power when population totals from the next census are used to draw new political districts in 2021.
The most recent evidence surfaced on Monday, when the Justice Department turned over 26 documents from Ms. Jones’s files to plaintiffs in the main lawsuit that challenged the citizenship question. The documents should have been disclosed during the legal battle over the question, but were “inadvertently not produced” by the Commerce Department, which oversees the bureau, the department said.
That followed the Nov. 12 release by the House Oversight and Reform Committee of a cache of previously undisclosed documents, most notably an email exchange with Mr. Hofeller and text messages to a senior Justice Department official by a key figure in the citizenship-question process, Mark Neuman. Mr. Neuman, a longtime friend of Mr. Hofeller, first raised the prospect of adding the question to the census while serving on President-elect Trump’s transition team. He later became an informal adviser to Commerce Secretary Wilbur L. Ross Jr. on census issues, including the citizenship question.
Those documents also had not been turned over to the plaintiffs in the census lawsuit, despite their request during discovery for evidence including “personal emails, text, messaging apps or personal devices or voicemails.”
The Justice Department stated last week that the missed documents were unimportant and their oversight was understandable, given that the administration had turned over some 154,000 other documents in the lawsuit. But the plaintiffs — who were already seeking court-ordered sanctions against the department for what they called deliberate efforts to conceal evidence — said the latest batches of overlooked documents were anything but trivial.
“It is interesting that each and every document that the administration ‘inadvertently’ failed to disclose is something that connects the dots between the citizenship question and a discriminatory scheme to dilute the political power of immigrant communities,” Dale Ho, a senior lawyer at the American Civil Liberties Union who represents some of the plaintiffs, said in an email. “If that’s just coincidence, it’s an awfully convenient one for an administration known for a casual relationship with the truth.”
The Justice Department and the Commerce Department, the leading players in the citizenship-question saga, have repeatedly insisted that politics played no role in their deliberations and that the law backs their refusal to surrender internal documents to critics. A Justice Department spokeswoman, Kerri Kupec, last week dismissed the House lawsuit over documents as “nothing more than a political stunt.”
None of the newly disclosed documents is conclusive. But a number do bear directly on central questions being pursued by the House committee and the lawsuit plaintiffs: whether placing a citizenship question on the census was a partisan political scheme meant to undercount residents in largely Democratic areas.
The Commerce Department added the citizenship question to the census in 2018 after the Department of Justice said it needed detailed information on where noncitizens live to enforce the 1965 Voting Rights Act. The Supreme Court called that rationale “contrived” when it blocked the question’s addition to the census in June.
Critics have long maintained that the Trump administration actually wanted a detailed count of noncitizens so that state legislatures could exclude them from census totals that will be the basis for redistricting in 2021.
Excluding noncitizens would reduce population counts in predominantly Democratic areas like big cities, where most noncitizens live, and shift political power to Republicans. Legislators in several Republican-controlled state legislatures have indicated that they will propose basing future political maps on citizen-only population totals, and President Trump indicated his support for that last summer.
Mr. Hofeller, the Republican Party’s chief redistricting strategist before his death last year, suggested to Mr. Neuman after Mr. Trump’s election that the presidential transition team add the citizenship question to its list of issues. One of the most notable documents released this past month by the House committee is a 2017 email in which Mr. Neuman asked Mr. Hofeller to help vet a legal argument ostensibly supporting the need for citizenship data to enforce the Voting Rights Act.
Mr. Hofeller’s business partner approved that language, which was incorporated into a draft of a request by the Justice Department to add the citizenship question to the census. An October 2017 text message containing that draft was sent by Mr. Neuman to the Justice Department’s top civil-rights official, John Gore, House committee documents show.
Plaintiffs in the census lawsuit have argued that those documents show a direct link between Mr. Hofeller and the Justice Department’s request, proving the need to look for further evidence in files that the administration has refused to release.
For its part, the Justice Department has asserted that Mr. Gore never met or heard of Mr. Hofeller and paid no attention to Mr. Neuman’s drafts when he eventually wrote the department’s formal request for the citizenship question.
In a letter filed in court this past week, however, the department did offer one concession: It is taking a closer look at its digital archive of citizenship-question evidence “to determine whether any other documents were similarly inadvertently omitted from production.”