A federal judge in Manhattan ruled Tuesday that the Trump administration’s decision to add a citizenship question to the 2020 census was unlawful.

In his ruling, Judge Jesse Furman, of the U.S. District Court for the Southern District of New York, said Commerce Secretary Wilbur Ross’s decision to add the question to the census was “arbitrary and capricious” and enjoined the administration from including it on the questionnaire.

{mosads}Furman, an Obama appointee, said Ross violated a statute that requires him to collect data through the acquisition and use of “administrative records” instead of through “direct inquiries” on a survey such as the census.

Ross announced in March that he was granting a request from the Justice Department to reinstate the citizenship question on the decennial population count to help the agency better enforce the Voting Rights Act.

The decision led to a flurry of lawsuits across the country.

In his 277-page ruling, Furman called Ross’s violations of the Administrative Procedures Act (APA) “egregious.”

“He failed to consider several important aspects of the problem; alternately ignored, cherry-picked, or badly misconstrued the evidence in the record before him; acted irrationally both in light of that evidence and his own stated decisional criteria; and failed to justify significant departures from past policies and practices — a veritable smorgasbord of classic, clear-cut APA violations,” he wrote.

Furman said he was unable to find that Ross’s decision to add the question was a pretext for impermissible discrimination, as the challengers had argued. The judge said that was due, in part, to the Supreme Court’s decision to temporarily block a court order that would have forced Ross to be questioned under oath.

“As defense counsel more or less conceded during closing arguments, a deposition of Secretary Ross would have been the best evidence of the question at the heart of the due process inquiry — namely, the true nature of Secretary Ross’s intent in reinstating the citizenship question,” Furman said.

The Supreme Court agreed in October to stay Ross’s deposition and a month later said it would review the dispute over the breadth of discovery in the case. Arguments in the case are scheduled for Feb. 19.

Furman’s ruling stems from two lawsuits that were consolidated — one brought by 18 blue states, the District of Columbia, 15 cities and counties, and the U.S. Conference of Mayors, and another brought by a coalition of immigrant rights groups.

Furman acknowledged that his ruling was long, but said it was for good reason.

“As noted, the population count has massive and lasting consequences,” he said. “And it occurs only once a decade, with no possibility of a do-over if it turns out to be flawed.”

The census count is used to redraw House districts and determine the number of House seats each state receives, as well as determine each state’s number of votes in the Electoral College. It’s also used to divvy up federal funding among the states.

The American Civil Liberties Union (ACLU) called Furman’s ruling a “forceful rebuke of the Trump administration’s attempt to weaponize the census for an attack on immigrant communities.”

“The evidence at trial, including from the government’s own witness, exposed how adding a citizenship question would wreck the once-in-a-decade count of the nation’s population,” Dale Ho, director of the ACLU’s Voting Rights Project, said in a statement.

“The inevitable result would have been — and the administration’s clear intent was — to strip federal resources and political representation from those needing it most.”

New York Attorney General Letitia James (D) said the ruling is a major win.

“The attempts by the Trump Administration to mandate a question about citizenship were not rooted in a desire to strengthen the census process and would only undermine our immigrant communities. Inciting fear in our residents is not only immoral, but also ill-conceived,” she said in a statement.

“Accurate population counts are imperative for allocating funding for critical programs and support systems and for determining fair representation in Congress and the Electoral College.”

The Justice Department said it was disappointed and still reviewing the court’s ruling when reached by email Tuesday morning.

“Secretary Ross, the only person with legal authority over the census, reasonably decided to reinstate a citizenship question on the 2020 census in response to the Department of Justice’s request for better citizenship data, to protect voters against racial discrimination,” Justice Department spokeswoman Kelly Laco said in a statement.

“Not only has the government asked a citizenship question in the census for most of the last 200 years, 41 million households have already answered it on the American Community Survey since 2005.”

Laco said the government is legally entitled to include a citizenship question on the census and people in the United States have a legal obligation to answer.

“Reinstating the citizenship question ultimately protects the right to vote and helps ensure free and fair elections for all Americans,” she said.

Updated at 11:20 a.m.