Special counsel Robert Mueller has submitted his final report to Attorney General Bill Barr in the Trump-Russia investigation.

And now begins the battle to make the Mueller report public.

The special counsel regulations require Mueller to write up his findings and submit them to the attorney general, which he did. And Barr notified Congress in a letter Friday that Mueller had concluded his investigation. But beyond that, he has a fair amount of discretion on what to share from the report both to Congress and to the public.

In his letter to Congress, which he made public, Barr told lawmakers that he remained “committed to as much transparency as possible,” and would work to determine “what other information from the report can be released to Congress and the public consistent with the law.”

The special counsel regulations do dictate that the attorney general can disclose information that’s in the public interest — and many would argue that Mueller’s report, whatever the findings contained in it may be, more than meets that standard.

Democrats in Congress have said they’re willing to fight to get access to the full findings, though that would likely mean doing battle with the Justice Department. Lawmakers from both parties called on the AG Friday to make as much information available as possible.

Pressure will be intense to make the bulk of Mueller’s conclusions public. The case has consumed the nation for nearly two years. The completion of the special counsel’s investigation could expose the scope of foreign interference in the US political system and explain whether Americans, including those on the Trump campaign, assisted toward that end. It could damn a sitting president, or exonerate him, either of which could change the course of his presidency.

Here’s a look at how the battle for the Mueller report might go down.

What we know (for real) about the possible Mueller report

The “Mueller report” has taken on an almost mythical quality. Some believe that the document will answer the question of whether the Trump campaign colluded with Russia in the 2016 election, tie up all the outstanding threads in the investigation, and explain whether President Trump or his associates attempted to obstruct justice in the course of that investigation.

But contrast that to the actual reporting requirements, as laid out in special counsel regulations:

At the conclusion of the Special Counsel’s work, he or she shall provide the Attorney General with a confidential report explaining the prosecution or declination decisions reached by the Special Counsel.

Mueller was required to turn in his confidential report to Barr. As the regulations stipulate, that document must outline the “prosecution or declination decisions” — so whom the special counsel chose to charge and prosecute, and whom he did not, and why he came to those conclusions.

“It doesn’t even have to be a detailed report,” Stephen Bates, a professor at the University of Nevada who’s written on this issue for Lawfare and other outlets, told me last month. “[Mueller] just would tell Barr, ‘I’m done. Here are the decisions I made about who not to prosecute, and why.’”

Barr was also required to notify and explain to Congress — specifically the committee chairs and ranking members of the Judiciary Committees in both chambers — that the special counsel completed his investigation. Barr was also bound to tell Congress whether, at any point in the investigation, the attorney general had overruled any “proposed action” by the special counsel.

Barr, in his letter to Congress, said that had not happened in the course of the investigation — another sign that Mueller’s work appears to have progressed unimpeded, at least under the oversight of Deputy Attorney General Rod Rosenstein and even acting Attorney General Matthew Whitaker.

But that’s pretty much it. Barr doesn’t have to turn over Mueller’s full report to Congress under the existing regulations. “He just tells Congress, ‘It’s over. And here are the cases in which I overrule Mueller’s judgment,’” Bates said.

What Barr has said about notifying Congress and the public

So the reporting requirements are minimal, especially when it comes to what Barr is obligated to tell Congress. But Barr can share more information either with lawmakers or directly with the public. Or as the Washington Post’s Greg Sargent argues, “There is nothing that precludes robust public disclosure of Mueller’s findings, and ... in a situation as unusual as this one, we are absolutely right to expect and insist on it.”

Barr said during his Senate confirmation hearing in January that he believed in the value of making sure “the public and Congress be informed of the results of the special counsel’s work.” But he was a bit evasive about what that meant in practical terms.

In the letter he sent to Congress on Friday, Barr told lawmakers that he would advise Congress on the special counsel’s “principal conclusions,” possibly as early as this weekend.

Barr then said he would consult with Rosenstein and Mueller “to determine what other information from the report can be released to Congress and the public consistent with the law, including the Special Counsel regulations, and the Department’s long-standing practices and policies.”

The special counsel regulations empower the attorney general to “determine that public release of these reports would be in the public interest, to the extent that release would comply with applicable legal restrictions.”

“Applicable legal restrictions” is probably the key phrase here for Barr. The Department of Justice follows certain guidelines and laws for criminal cases on what information can be shared with the public and what information cannot.

Remember, Mueller’s report has to include his “prosecution or declination decisions.” And the special counsel has, to a large extent, explained his prosecution decisions in indictments and other court filings, even with redactions.

It’s much trickier when it comes to people Mueller declined to prosecute. The Justice Department typically doesn’t release damaging information about people if they’re not charged with any specific crimes, or explain why a matter doesn’t rise to criminal prosecution.

And while it does happen, it’s done rarely and often in extraordinary circumstances. There is, of course, a recent high-profile precedent: then-FBI DirectorJames Comey’s controversial, and much-criticized, statement on the investigation into Hillary Clinton during the 2016 election, where he called Clinton “extremely careless” in her email practices but said it didn’t rise to the level of prosecution.

Of course, this is all much more fraught in the matter of President Trump himself, who under Justice Department guidelines can’t be indicted while in office — but can face political consequences, specifically impeachment. This is the “elephant in the room” when it comes to the Mueller report, as my colleague Andrew Prokop wrote. (You can read his full explainer here.)

There are other legitimate legal reasons that might prevent Barr from disclosing information. Mueller might rely on grand jury evidence and testimony, and there are rules against making this information public outside the DOJ if the case isn’t being prosecuted.

The report might also contain classified information or sources, likely related to national security, which can’t be disclosed because it involves sensitive matters or reveals sources or methods of intelligence-gathering.

Issues of executive privilege might crop up, which Barr also brought up in his Senate hearing. Barr said, in theory, it was possible that Trump could exert executive privilege, which would lead to a fight with the White House over which matters in Mueller’s report can be made public.

At the same time, Barr was asked by Sen. Patrick Leahy (D-VT) during his hearings whether he would share Mueller’s findings with the president to let him or his lawyers put their “spin” on it before it was released. Barr responded, “That will not happen.”

The attorney general is undoubtedly going to take all of these issues into consideration. Whatever he decides to turn over to Congress may be redacted or summarized to address those concerns. But he also has to weigh the public’s need or right to know about Mueller’s conclusions. And there’s a strong argument to be made in favor of this.

Mark Tuohey, a lawyer at BakerHostetler who helped shape the special counsel regulations and testified to Congress about them in 1999, told me that when the attorney general reviews the report, or shortly after, he has to determine whether “the public release of the Mueller report would be in the public interest, which I think it very much is.”

If Congress gets the report, it will likely get released to the public. But expect court battles along the way.

The calls for Barr to make the report public began immediately on Friday.

Speaker of the House Nancy Pelosi and Senate Minority Leader Chuck Schumer said in a statement that “it is imperative for Mr. Barr to make the full report public and provide its underlying documentation and findings to Congress.”

Senate Majority Leader Mitch McConnell also welcomed the end of the Mueller investigation. “The Attorney General has said he intends to provide as much information as possible,” McConnell said in a statement. “As I have said previously, I sincerely hope he will do so as soon as he can, and with as much openness and transparency as possible.”`

More likely, the disclosure of the Mueller report will probably play out in stages. Barr will submit some version of the report to Congress, which potentially might include redactions, or present a summary of the findings. Barr could also potentially transmit the full report to select lawmakers in Congress, as is often done with classified materials.

Again, much of this depends on what Mueller’s report contains, how it’s written, and what conclusions he reaches. But whatever Congress receives is very likely going to reach the public.

Richard Pildes, a law professor at New York University, told me that if the report lays out evidence that crimes have been committed, that’s even more of a case for Congress and the public to see the report.

“Congress, in carrying out its oversights function, including if there is any consideration of impeachment in light of what the report finds — certainly those facts are going to be made public,” Pildes said.

And whatever Barr submits to Congress is probably not the final word on the Mueller report.

“I think the submission of the report will be the beginning of a process that will go back and forth a bit and could very well involve matters being brought before the District Court,” Tuohey said.

Congress might demand more information than Barr was willing to initially turn over. Democrats have already said they’ll subpoena to get the full findings. Republicans, too — particularly those skeptical of the Russia investigation — have said they want to see all of Mueller’s evidence.

There’s the possibility of a fight over confidential grand jury information between the Justice Department and Congress, which might end up in the court, with a judge forced to make a decision. Congress could also attempt to use its subpoena powers, even bringing in Mueller himself to testify on his conclusions.

Barr has discretion, sure. But Congress looks ready to exhaust all options to make Mueller’s findings public.

The public really wants to know Mueller’s findings. That’s no small thing.

Barr, who’s been on the job since February, is still something of an enigma as attorney general, which has made the speculation over what he might do with the Mueller report even more intense — and probably a bit fruitless.

But we do know one thing: Barr will be under enormous pressure to release this report. According to a recent Washington Post/Schar School poll, 81 percent of Americans believe the Mueller report should be released in full. That includes both Democrats and Republicans.

That’s because this isn’t just about the public wanting to know — the information is critical to our democracy and rule of law. This is an investigation into whether the president of the United States, or those close to him, coordinated with a foreign adversary to sway an election.

Americans have a right to know Trump’s culpability, or whether he obstructed justice in the course of the investigation. They also must know if the president is fully cleared of any wrongdoing. Either requires evidence to back up the finding.

“If the attorney general decides that the release is not in the public interest, there’s going to be a huge battle over that,” Tuohey told me. But he didn’t think that was going to happen. “I don’t believe that’s a decision he would make, given the fact this is so public and has been a public matter in terms of congressional hearings and the like,” he said.

And a lot of Mueller’s findings are already in the public sphere. Mueller and his team have put together “speaking indictments,” which add more detail than is normally required and offer a comprehensive narrative about crimes alleged and how they were carried out.

Mueller and his prosecutorial team have been careful and purposeful in what they’ve shown the public so far. And the special counsel, depending on what he concludes, may also believe it’s imperative to make his findings public.

Mueller may be expected to carefully follow the special counsel guidelines, but as some have pointed out, he can also write a report designed for the public to see, with minimal confidential grand jury testimony or classified details.

That won’t stop the yearning for some overarching road map, with all the gray areas and unknowns filled it. But there’s a possibility that Mueller will never deliver that. He may never offer a definitive answer to the question of “collusion” or “no collusion.” Almost no one has any idea what he’ll write or what evidence he’ll present — except maybe the special counsel himself.

Now that Mueller has submitted his report, Barr looks prepared to stick to his promise “to make as much information available as I can consistent with the rules and regulations” of the special counsel.

The question is whether that will be enough for Congress, and the rest of America.