From the moment it was announced in March, the decision to add a question about citizenship to the 2020 census was described by critics as a ploy to discourage immigrants from filling out the form and improve Republican political fortunes. The Commerce Department, which made the decision, insisted that sound policy, not politics, was its sole motivation.
Now a federal lawsuit seeking to block the question has cast doubt on the department’s explanation and the veracity of the man who offered it, Commerce Secretary Wilbur L. Ross Jr. And it has given the plaintiffs in the suit — attorneys general for 17 states, the District of Columbia and a host of cities and counties — broad leeway to search for evidence that the critics are correct.
In a hearing last week in the United States District Court in Manhattan, Judge Jesse M. Furman gave the plaintiffs permission to search government files and take sworn testimony from up to 10 administration officials in an effort to discover how and why the citizenship decision was made.
The administration has claimed that better data on the citizenship of voting-age adults was needed to enforce the Voting Rights Act. But additional evidence could cast doubt on that explanation and potentially lay the groundwork for the question’s removal from the 2020 census.
After Mr. Ross’s explanation for the citizenship question’s origin shifted, Judge Furman said it appeared that the Commerce Department had acted in “bad faith” in deciding to add the question.
Mr. Ross said in a statement on March 26 that the Justice Department, which oversees enforcement of the Voting Rights Act, had asked that the question be placed on census forms. But late last month he reversed course, stating in a memo that he actually had been discussing the citizenship question “with other government officials” since shortly after taking office in February 2017 — and that the Justice Department had made its request only after he or his aides asked it to.
Judge Furman called Mr. Ross’s March explanation of his decision both “potentially untrue” and improbable because, he said, the Justice Department “has shown little interest in enforcing the Voting Rights Act.”
The Commerce Department declined to comment on the record about the lawsuit.
Terri Ann Lowenthal, a former congressional expert on the census who is a private consultant to groups seeking an accurate 2020 count, called Mr. Ross’s revised timeline “disappointing and deeply troubling.”
“This seems to confirm that the Justice Department request for the citizenship question was a pretense to achieve a political goal through the census,” she said. “The pieces of the puzzle are starting to fit together, going back to when President Trump took office.”
In their lawsuit, which is led by the New York attorney general, Barbara D. Underwood, the plaintiffs imply that enforcing the Voting Rights Act was a pretext for another goal: ensuring that the nation’s 11 million-plus undocumented immigrants are not counted for the purpose of drawing congressional and other political districts, which are required to have equal populations.
The practical impact would be to reduce the number of congressional districts, and therefore Electoral College votes, in states with large numbers of noncitizens — often, though not always, Democratic strongholds.
Mr. Ross has not named the administration officials with whom he discussed the citizenship question after taking office. But other lawsuit documents released last month show that Mr. Ross received an email in July 2017 from Kris W. Kobach, the Kansas secretary of state who has taken a strong position against illegal immigration. Mr. Kobach urged Mr. Ross to add the citizenship question to the 2020 census because undocumented immigrants “do not actually ‘reside’ in the United States” but are counted for reapportionment purposes.
Mr. Kobach noted in the email that he had recently reached out to Mr. Ross “on the direction of Steve Bannon,” who was then the White House chief strategist. Documenting the extent of outsiders’ role in the citizenship decision will be a priority when the plaintiffs’ search for new evidence begins, experts said.
“That suggests very strongly that the directive here was ultimately a directive that came from the White House,” said Thomas Wolf, counsel at the democracy program of the Brennan Center for Justice at N.Y.U. School of Law.
The census tally, which includes everyone living in the United States regardless of immigration status, is used to reapportion political boundaries every 10 years to account for population changes. But a growing movement on the far right seeks to exclude undocumented immigrants from being counted during reapportionment; Alabama’s Republican secretary of state filed a lawsuit in May seeking to do exactly that.
If only citizens were counted for reapportionment, “California would give up several congressional seats to states that actually honor our Constitution and federal law,” one leader of the anti-immigrant movement, Representative Steve King, Republican of Iowa, said in February.
That is, for now, a distant prospect. But some experts say they believe asking about citizenship could accomplish the same goal by discouraging undocumented immigrants, even legal ones, from being counted.
“Their actions can produce a census that leaves out many of the people they don’t want counted for political representation,” Ms. Lowenthal said. “And there will be consequences, perhaps, well beyond what immigration hard-liners believe will only be reduced numbers in selected states.”