“In light of the ... arguments and legal principles, making a responsible de novo determination of NSA’s exemption claims requires in camera review,” Kollar-Kotelly, an appointee of President Bill Clinton, wrote.

The Justice Department has argued that the entire memo is classified and exempt from disclosure under a form of executive privilege, because the document describes a confidential conversation between the president and a top adviser.

The watchdog group pressing for the memo’s release, the Protect Democracy project, contends that the privilege was waived after special counsel Robert Mueller included a summary of the conversation in his report that was published last year.

Kollar-Kotelly said it is simply too hard for her to resolve those issues without seeing the memo herself.

“The Court must consider whether the relevant information in the Ledgett Memorandum has been officially acknowledged, which requires close comparison of the relevant information disclosed in the Mueller Report and the relevant information contained in the Ledgett Memorandum,” she wrote in her eight-page decision.

Kollar-Kotellly’s order was particularly notable because it came just one day after another judge on the same court ordered an in camera review of the Mueller report itself. That judge, Reggie Walton, said in a scathing opinion the review was needed because Attorney General Bill Barr had a pattern of misleading statements about the contents of the report.

Historically, in camera review by judges in Freedom of Information Act cases is unusual, although the preeminent transparency statute explicitly authorizes such assessments. The back-to-back rulings this week suggest that some judges are increasingly unwilling to take at face value representations from the Trump administration about the contents of documents being withheld in FOIA cases.

Kollar-Kotelly ordered NSA to give her access to the Ledgett memo by March 13. She invited the agency to advise her if any special procedures were necessary because of to the sensitive nature of the document.

Spokespeople for the Justice Department and the NSA did not immediately respond to requests for comment on the ruling.

Ben Berwick, counsel at Protect Democracy, said he’s “grateful the Court has now chosen to look at this memo for itself and determine whether the government is inappropriately asserting privileges in order to hide presidential wrongdoing.”

