The judge presiding over the Department of Justice’s attempt to add a citizenship question to the 2020 Census blocked the department’s request to replace its entire legal team on the case, asserting that they had not given sufficient reason for doing so.

The Trump administration had announced earlier this week that it planned to swap out all the lawyers arguing for the question’s inclusion without providing a reason why. Sources familiar with the matter say that the decision was partially driven by the frustration of career lawyers in the department over the way the case was being handled and the thin legal basis that they were being forced to defend.

The judge overseeing the case, U.S. District Judge Jesse M. Furman, denied the DOJ’s request to refresh its legal team. “Defendants provide no reasons, let alone ‘satisfactory reasons,’ for the substitution of counsel,” he wrote. Furman also noted that a case filing was due in three days, and that the Trump administration had previously stressed the urgency of the case as the census forms needed to be printed as soon as possible. “If anything, that urgency — and the need for efficient judicial proceedings — has only grown since that time,” Furman wrote.

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He acknowledged that if the Justice Department provided an adequate explanation for why it wanted to bring in a new team of experts then it would be allowed to do so, as long as the old team remained available in case they were needed. He stressed the urgency of the case, and added that if it wanted to bring in new lawyers the DOJ would have to “file an affidavit providing unequivocal assurances that the substitution of counsel will not delay further litigation of this case (or any future related case).”

Attacking Furman’s decision, President Donald Trump tweeted, “So now the Obama appointed judge on the Census case (Are you a Citizen of the United States?) won’t let the Justice Department use the lawyers that it wants to use. Could this be a first?”