U.S. Commerce Secretary Wilbur Ross. (Kevin Lamarque/Reuters)

A federal judge Tuesday allowed a multistate lawsuit to move forward amid “strong” evidence that the Trump administration acted in bad faith in its push for a controversial citizenship question to be added to the 2020 Census, plaintiffs in the case said.

Judge Jesse Furman of Manhattan’s Southern District also granted a request for discovery, according to New York Attorney General Barbara Underwood, whose office filed the case on behalf of 18 states, the District of Columbia, nine cities, four counties and the U.S. Conference of Mayors.

The judge gave the defendants, which include the Commerce Department, Commerce Secretary Wilbur Ross, and the Census Bureau and its acting director until July 23 to add documents from the Commerce and Justice departments, detail the documents they refuse to produce and give a basis for the refusal.

Furman said he would allow depositions of up to 10 people from both departments. He said he would rule shortly on the government’s motion to dismiss.

Hailing the decision as a “major win,” Underwood said, “By demanding the citizenship status of each resident, the Trump administration is breaking with decades of policy and potentially causing a major undercount that would threaten billions in federal funds and New York’s fair representation in Congress and the electoral college.”

A Commerce Department representative said: “We are disappointed that the court in New York did not defer fact discovery until after a ruling on a motion to dismiss. We are confident that the plaintiffs’ case is without merit, that any allegations of bad faith are specious, and that we will prevail in court.” The Justice Department declined to comment.

Litigation began almost immediately after Ross announced in March that a citizenship question would be added to the 2020 questionnaire; at least six lawsuits have been filed contesting it. At the time, Ross told lawmakers he was responding to a December 2017 request by the Justice Department to add the question to better enforce the 1965 Voting Rights Act.

Critics say the question, which has not appeared on a decennial survey since 1950, is not necessary for that purpose and that it is a political move meant to reduce response rates among immigrants and their families. Data from the census is used to draw legislative districts, reallocate congressional seats and determine how hundreds of millions of dollars in federal funds are spent.

Documents released by the Commerce Department in early June as part of the lawsuits indicated that former Kansas secretary of state Kris Kobach and former Trump strategist Stephen K. Bannon had been involved in discussions about the question the previous summer. They also included an analysis by the Census Bureau’s chief scientist warning that adding the question would lead to a less accurate, more costly count.

The plot thickened last month when Ross filed an unexpected memo in the case revealing that he was considering adding the question when he began his job in February 2017 after hearing from other senior administration officials on the subject.

The memo contradicted his earlier sworn testimony on the timing and provenance of the request and appeared to indicate that he was actively discussing the question far earlier than he had indicated.

“It now appears those statements were potentially untrue,” Furman said Tuesday, according to Courthouse News.

Furman’s decision came a day after 17 Senate Democrats sent a letter asking Ross to release “all informal & formal documents” related to adding the question.

Arturo Vargas, executive director of NALEO, an organization that advocates for Latino civic engagement, hailed the ruling. “The judge . . . acknowledged that the secretary of commerce has not been completely truthful in explaining his actions and motivations,” he said. “By requiring the government to disclose additional documents, the judge is appropriately holding the administration accountable.”