A federal judge in New York ruled the US Department of Justice can’t replace nine lawyers on the legal team arguing the controversial dispute over whether the administration can add a citizenship question to the 2020 census without explaining why it wants to swap out the lawyers.

The justice department announced this week that it was appointing a new team of lawyers to take over census-related cases, after the supreme court upheld a lower court decision rejecting the commerce department’s stated justification for adding a citizenship question to the census.

But US district judge Jesse M Furman, who earlier this year ruled against adding the citizenship question, ruled on Tuesday that the justice department provided “no reasons, let alone ‘satisfactory reasons’, for the substitution of counsel”.

The justice department had announced the changes in a three-paragraph notification that argued the replacements wouldn’t “cause any disruption in this matter”.

Furman called the department’s request “patently deficient”, except for two lawyers who have left the department or the civil division which is handling the case.

The changes in the legal team came about after a top justice department civil attorney who was leading the litigation effort told the attorney general, William Barr, that multiple people on the team preferred not to continue, Barr told the Associated Press on Monday.

The attorney who was leading the team, James Burnham, “indicated it was a logical breaking point since a new decision would be made and the issue going forward would hopefully be separate from the historical debates”, Barr said.

Tuesday’s ruling is the latest in the controversy around the citizenship question.

Civil rights groups have argued that asking about citizenship status may discourage immigrants from participating in the census, producing an undercount of immigrants, particularly immigrants of color, in official tallies.

Following the supreme court’s decision two weeks ago, the commerce department’s Census Bureau began printing census questionnaires without the question and the Department of Justice signaled it would not attempt to continue the legal fight.

But the department reversed itself after Donald Trump promised to keep trying to add the question and notified judges in three similar legal challenges that it planned to find a new legal path to adding the question to the census.

Furman said the urgency to resolve legal claims and the need for efficient judicial proceedings was an important consideration in rejecting a replacement of lawyers.

He said the justice department had insisted that the speedy resolution of lawsuits against adding the question was “a matter of great private and public importance”.

“If anything, that urgency, and the need for efficient judicial proceedings, has only grown since that time,” Furman said.

Furman said the government could re-submit its request to replace attorneys only with a sworn statement by each lawyer explaining satisfactory reasons to withdraw so late. He said he’ll require new attorneys to promise personnel changes will not slow the case.