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Judge Amy Berman Jackson ruled Monday that the Justice Department must release a March 2019 memo about its decision not to charge former President Donald Trump with obstruction of justice at the conclusion of former Special Counsel Robert Mueller's investigation into Russian interference in the 2016 election.

The Justice Department argued that the memo was legal reasoning that helped former Attorney General William Barr decide against charging Trump with obstruction. In her opinion, released Tuesday, Jackson said she believed Barr and his top advisers had already decided Trump shouldn't be charged, and the memo was strategic planning. As such, she ruled, the memo can be released to the public.

Before the Mueller report was released, Barr wrote a letter giving his summation of it, which Trump used to claim he had been exonerated. Jackson wrote that Barr's "characterization of what he'd hardly had time to skim, much less study closely, prompted an immediate reaction, as politicians and pundits took to their microphones and Twitter feeds to decry what they feared was an attempt to hide the ball."

Barr was "disingenuous" both when the obstruction memo was written and the Justice Department appeared before her court to argue that the memo should stay secret, Jackson said. "The agency's redactions and incomplete explanations obfuscate the true purpose of the memorandum, and the excised portions belie the notion that it fell to the attorney general to make a prosecution decision or that any such decision was on the table at any time."

The Citizens for Responsibility and Ethics in Washington organization has used the Freedom of Information Act to try to get access to Justice Department documents about the Mueller probe. "We requested these records and filed this lawsuit due to serious doubts about the official story coming out of Barr's DOJ," CREW spokesman Jordan Libowitz told CNN on Tuesday. "While we do not yet know what is in the memo, the court's opinion gives us confidence that we were right to have questions." The government — now under the Biden administration — has until May 17 to appeal Jackson's ruling.