Attorney General Merrick Garland is contesting a court order that would require disclosure of an internal Department of Justice memo sent to former AG Bill Barr. The subject: why not to prosecute Donald Trump.

Garland's decision is a Rorschach test for anyone interested in restoring normalcy and credibility to the Department of Justice after the institutional bloodbath of the Trump years.

From the standpoint of transparency and openness, the public should see the memo to better understand what went wrong in Trump's DOJ. But from the standpoint of returning to the department's traditional norms — including the norm of depoliticizing criminal prosecution decisions — the refusal to disclose is weirdly reassuring. It's a sign that the Biden Department of Justice will reaffirm the department's commitment to confidentiality and not use the DOJ, as Trump tried to, to score political points.

I realize this second way of seeing the inkblot is counterintuitive and, to some, frustrating. So I'm not going to urge it on you. I'm just going to explain it, even while acknowledging the validity of the first, disclosure-oriented interpretation.

It's easy to understand the impulse that the department should publish the confidential memo. It was prepared for Barr by the Office of Legal Counsel, the section of the DOJ that is ordinarily in charge of telling the executive branch whether a proposed executive action is lawful and constitutional.

In this instance, Barr asked the OLC to do something a little different. He asked them to review special counsel Robert Mueller's report on Trump and obstruction of justice and tell him whether it provided enough evidence to charge Trump with a crime.

The OLC had already issued guidelines that it was not constitutionally permissible for the U.S. government to prosecute Trump (or any sitting president). What Barr wanted to know was whether, under ordinary Justice Department prosecuting guidelines, the report provided enough evidence to charge Trump with a crime — even though he could not be prosecuted for one.

Judging by the memo's first page and a half — which Garland released under pressure from a federal district judge in Washington, D.C. — the OLC said that the Mueller report did not contain enough evidence to justify charging Trump with obstruction of justice. What we don't know is what the reasoning was. That is contained in the rest of the memo, which Garland doesn't want to disclose.

At the time the memo was written, the Mueller report hadn't yet been released to the world. And Barr purported to rely on the memo when he made his now-famous, misleading announcement of the Mueller report's findings. In that announcement, you will recall, Barr said that the Mueller report had not recommended prosecution and for that reason he had decided not to prosecute Trump.

From this it follows that the public has a real interest in knowing what the memo said. It's not so much that we can't guess: Presumably, the memo went through the report's action-by-action analysis of Trump's problematic behavior and concluded each time that there wasn't enough basis to launch a criminal prosecution. Nonetheless, the memo was a highly unusual document. The OLC usually has nothing to do with prosecution decisions. But here, it drafted a memo for the highly political purpose of giving Barr cover in deciding not to prosecute his boss. The full memo would likely show just how deeply politicized the OLC became under Barr.

That leads us to the counterintuitive reading of the Rorschach test. As a general matter, the Department of Justice never wants to disclose its internal deliberations about whether to prosecute somebody. You can see why: If the decision is made to prosecute, the department wants to present its strongest case. It doesn't want to reveal its own analysis of the weakest parts of that case. But on the other hand, if the department decides not to prosecute, it doesn't want its decision second-guessed. It also realizes that it would be bad for private citizens who have been investigated but not prosecuted to have a government document out there describing unproven, uncharged crimes.

For these plausible reasons, Garland wants to keep the OLC memo secret. But that's not all. By resisting disclosure, Garland is sending a message to DOJ employees that he's treating the Barr-era OLC's decisions as normal, rather than as aberrant. That is, he is placing the institutional interests of the department ahead of the political interests of Democrats. He's also avoiding an episode of public criticism of the OLC and what happened there under Barr and Trump, and reminding us all that decisions about prosecution should not be politicized.

If you take this reading of the inkblot seriously, then you've got some insight into how an old-line Justice Department insider like Garland plans to build trust in the department internally and restore credibility externally. Departmental self-interest is business as usual in Washington, D.C. Most of the time, that's not a good thing. But this time, it may be a hopeful sign.

Noah Feldman is a Bloomberg Opinion columnist and host of the podcast "Deep Background." He is a professor of law at Harvard University and was a clerk to U.S. Supreme Court Justice David Souter. His books include "The Three Lives of James Madison: Genius, Partisan, President."