AS WASHINGTON prepared for the release of special counsel Robert S. Mueller III’s final report, a fight was brewing between House Democrats and the Justice Department about how much would be redacted. House Judiciary Committee Chairman Jerrold Nadler (D-N.Y.) has prepared a subpoena demanding disclosure of the whole document to Congress. Attorney General William P. Barr has steadfastly insisted that information that is classified, stemming from secret grand jury proceedings, or otherwise sensitive would not be revealed publicly.

Mr. Barr is essentially asking Congress and the public to take him at his word that his redactions will be proper. There is already cause for wariness about Mr. Barr’s judgment, following reports that those who worked on the Mueller investigation felt that the summary the attorney general released last month inadequately represented their findings. That Mr. Barr rejected the notion that President Trump obstructed justice, even though Mr. Mueller made no determination on the matter, is another concerning sign about what the attorney general is thinking.

More important, Mr. Barr works for an administration preparing for all-out war with Congress over all sorts of disclosure, which would be only the latest in a string of bad-faith rejections of federal rules and traditional norms. Regardless of the attorney general’s reputation, he still works for an administration that long ago lost any benefit of the doubt on transparency and fair play.

There may be no satisfying end to this national saga until an independent referee steps in to sort out the controversy. Reggie Walton, a U.S. district judge, raised on Tuesday one possibility for further review. Accusing Mr. Barr of creating “an environment that has caused a significant part of the public . . . to be concerned about whether or not there is full transparency,” the judge raised the possibility that he would demand an unredacted copy to review whether the Justice Department’s omissions were warranted. We hope he follows through. Mr. Walton could ensure that the redactions followed Freedom of Information Act procedures and were not influenced by political considerations.

That would still leave the question of whether Congress should have full access to the unredacted document, as Democrats want. Separate legal proceedings initiated by House Democrats would have to consider tricky questions of what one branch of government owes another.

Transparency won out during the Watergate crisis and in the Bill Clinton impeachment battle. Even if judges determine that some elements of the Mueller report cannot be shared with the public, members of Congress have a serious claim that they should have wider access, as they do regularly to classified information in other contexts.

The Mueller investigation and its report have consumed national attention for many months, and rightly so: They concern a foreign attack on the nation’s democracy, the reactions of the country’s leaders and the task that faces policymakers in securing democratic institutions against future intrusions. This is not a time for timidity on transparency.