I have a confession: I don’t understand the reaction to the news of the Mueller investigation’s end. I don’t understand the evident glee among some of the president’s defenders. I don’t understand the gloom among some of the president’s critics. I don’t understand either why people seem surprised at news that has been foreshadowed for months in a sequence of stories by good reporters in a variety of different reputable news outlets.

The news we have learned so far about the investigation’s end is broadly consistent with everything we previously knew. It is consistent with Robert Mueller having conducted a vigorous probe. It is consistent with his having prosecuted a raft of suspects both for Russian interference in the 2016 election campaign and—on the U.S. side—for lying about interactions with Russian officials and cutouts. It is consistent with Mueller’s having investigated and prosecuted various possible obstructions of the probe. And it is consistent with his having largely finished his work and written a report detailing his findings, having also investigated a variety of matters that did not pan out into additional criminal charges.

Certainly, the end of the investigation is good news for those people who thought they might be facing indictment at its hands. And yes, many people have invested a great deal of political hope in the Mueller investigation.

But the measure of the investigation’s success or failure was never to be whether it brought down Donald Trump. It was not whether it indicted Trump’s children. And it was emphatically not whether it vindicated any individual person’s assumptions about what must have happened—including, by the way, my own.

The measure of success for the Mueller investigation was always whether the matters handed to it were investigated thoroughly and completely and prosecuted fairly and justly, and whether the counterintelligence concerns that gave rise to the probe were addressed seriously. The end of the investigation is thus, first and foremost, an occasion for relief that this has apparently taken place to the satisfaction of one Robert Swann Mueller, III. This is no small democratic accomplishment, and it was not a foregone conclusion in an environment in which the president has repeatedly sought to smear and frustrate the investigation—and even sought to remove Mueller from its helm.

I say all this without knowing whether, when Attorney General Bill Barr announces Mueller’s “principal findings” this weekend, they will prove to be helpful or harmful to President Trump, much less whether the report that underlies that announcement will help or hurt the president.

The fact that the investigation was able to take place is an enormous win, one for which we should all be grateful. And if its net results are the indictments and pleas Mueller has already garnered and some claim of vindication by everyone else, including the president, color me a satisfied taxpayer.

And having said that, let me go on to say that I have no idea what to expect from here, and I’m honestly not sure why anyone else is eager to go out on a limb—any limb—as to who the winners and losers in the investigation’s end are likely to be.

When a high-profile criminal investigation ends, a certain set of understandings normally guides what conclusions observers can and cannot responsibly draw about those who have escaped uncharged. These understandings work because they flow from a common set of assumptions about why the investigation has ended.

To be specific, we generally do not construe the failure of an indictment to materialize as evidence of innocence on the part of an investigative subject, the standards of criminal prosecution being high both in terms of the quality and the quantity of evidence. That said, we generally do interpret what is called a declination as suggesting that prosecutors lacked adequate admissible evidence to prove guilt beyond a reasonable doubt.

When a high-profile examination of a political scandal winds down without charges, therefore, we generally assume that the investigation is ending because of some deficiency in the evidence that makes proceeding with a prosecution unsound. And we consequently treat the end of the investigation as a moment at which the judgment of history and politics and morality naturally separate themselves from the judgment of the criminal law.

There are, of course, cases in which criminal probes end not merely because the facts are insufficient to indict or convict the subject but because the facts as found prove the subject’s innocence in some material respect—in other words, because the investigation has not merely not implicated the subject but actually cleared her. These cases do happen, and they are dramatic when they do. But the “clearing” of the subject is not what the end of a criminal probe normally means.

The end of a criminal investigation is thus a funny moment. While the subject will generally claim vindication, it actually does not mean that you cannot judge her conduct morally. It does not mean that she cannot be held accountable in myriad non-criminal fashions. She can be ridiculed. You can campaign against her on the basis of the unindicted conduct. You can write histories of the scandal that denounce her behavior. You might even be able to sue her successfully. The end of the investigation only means that the state will not punish her using the specific instrumentality of the criminal law. It means only that the we won’t “lock her up.”

Those are the rules in a normal criminal investigation, and they may well apply here to everyone who is not the president.

But the end of the Mueller investigation adds a number of layers of complexity to this already textured analytical framework—particularly as to Trump himself. For starters, it’s not entirely clear what exactly is ending with the close of the Mueller investigation. We know that Mueller submitted his report to Barr and that he reportedly won’t be seeking additional indictments. Because the May 2017 letter from Rosenstein to Mueller defining Mueller’s charter specified that he could investigate “any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump; and any matters that arose . . . directly from [that] investigation,” we can infer that indictments will not issue over, say, the Trump Tower meeting or the promise of “dirt” on Hillary Clinton. We can assume that the investigation of these matters is over.

But we also know that a number of loose ends remain unresolved. Cases remain pending; grand jury matters remain ongoing; and one subject was offered a plea agreement, declined it, leaked the documents provided to him by the special counsel, and yet remains uncharged; defendants who have pleaded guilty are still cooperating. Moreover, other investigations remain open and active, investigations which spun off of the Mueller probe. Some of these lines of investigative and prosecutorial work have been spun out publicly—for example, the Michael Cohen investigation in the Southern District of New York. Others may have been spun out in a non-public fashion.

More importantly, we actually don’t know why the probe has ended. And as to President Trump, this point is critical.

As a general matter, declinations fall into three broad categories: factual declinations, legal declinations, and prudential declinations. These overlap to some degree, and the distinctions here are thus somewhat artificial—though I hope still useful. A declination for factual reasons could be based on a finding of actual innocence—as discussed above—or a finding that the evidence, though compelling, is not adequate for prosecution. How much of a vindication or how politically damaging such a declination is depends entirely on the factual findings, about which we know nothing.

A declination for legal reasons is also preponderantly likely here, irrespective of the facts, at least as regards Trump himself. Indeed, we always knew that the investigation would not result in Trump’s indictment while he remained in office; that was never in doubt. For all the feverish discussion of the question of whether a president can or cannot be indicted, the Justice Department’s Office of Legal Counsel has a longstanding opinion on the matter that binds Mueller. There was never any chance that Mueller would defy this opinion. And there was thus never any chance either that Mueller would indict Trump while he remained in office. The result is that at least as regards the president himself, we cannot presume—as we normally would presume—that the investigation’s end means that the evidence is insufficient to bring charges. It might well mean that, and nobody should be surprised if it does. But it needn’t mean that.

There are other possibilities too. What if Mueller developed compelling evidence of presidential misconduct but that evidence does not map cleanly onto known criminal statutes? This could be the case on the collusion prong of the investigation, because knowingly and gleefully benefiting from a foreign power’s theft and disclosure of a political opponent’s emails isn’t, without more, a crime. And it could also be the case with respect to the obstruction component of the investigation, because the president has plausible arguments with respect to many of his obstructive acts that they are within his Article II powers.

There are also prudential factors that can lead to declinations—for example, the unwillingness to declassify material to bring a case. I have no reason to believe such factors are at work here. My point is simply that to say that Mueller is not recommending further charges does not tell you all that much unless you know why he’s not recommending further charges. Yes, it is possible that Mueller has concluded that the president is innocent, that there was “NO COLLUSION” and that there’s nothing to see here and we should all move on. But it’s also possible that he has concluded that the president is guilty as sin but he can’t prove this without outing a particular intelligence channel that NSA senior leadership would lie down in traffic to prevent him from discussing in court—and that even if he could blow that capability, the president can’t be indicted anyway and would have a good argument that his conduct was lawful. These scenarios are both consistent with Friday’s news.

What’s more, not all of the fundamental questions—and not necessarily the most important questions—at issue in this investigation were criminal questions to begin with. L’Affaire Russe began with a series of counterintelligence questions, after all, questions that interact with criminal matters but are not coextensive with them; these questions involved whether individuals associated with Trump’s campaign were being targeted by Russian intelligence, and they matured eventually to questions of whether the president himself sought to shut down the Russia investigation to the benefit of a foreign power.

Nor are the questions related to the acceptability of the president’s conduct the same as the questions of the indictability of that conduct. Moral acceptability is not a matter for a criminal prosecutor to determine, except insofar as Congress writes its standards into the criminal code. Beyond that, with respect to elected officials, it is a matter of political judgment—that is, what we as a society choose to accept from our officeholders both as an electorate and through our representatives in the impeachment process.

Relatedly, there are the fundamental narrative questions here: What happened? Who did what? And what does Congress want to do about it legislatively, if anything? A criminal investigation is not about telling a story, much less is it about providing a record for legislation.

This is why it was so wrong to make the Mueller investigation the end all and be all of accountability for L’Affaire Russe in the first place. It is why Susan Hennessey and I argued repeatedly that Congress had an independent duty to investigate the whole panoply of issues and not simply leave the matter to investigation by the executive branch. As the two of us put it back in February of 2017, long before Mueller was even appointed:

While the subject matter overlaps, the executive branch and the legislative branch are conducting different investigations for different purposes. Namely, the executive branch is conducting a set of foreign intelligence and counterintelligence investigations that may (or may not) have criminal investigative elements. Its goal is not to answer public questions about what happened or what may still be happening. By contrast, Congress is charged with ascertaining information related to legislative purposes—including the imposition of sanctions in response to the activity of a hostile foreign power, the discharging of its oversight function with regard to fraud, abuse, or corruption in the executive branch, and legislative measures that might be necessary to protect the American electoral system. It also has a duty to publicly address major questions the political system is struggling with now in a fashion the public can absorb and process: What is the President’s relationship with Russia? And is there reason to be concerned about it?

Because a criminal investigation is not designed to answer these questions comprehensively, its end cannot put them to rest.

What a criminal investigation can do, and what it may have done here, is to provide a text that offers a factual record which might be redeployed for purposes of answering non-criminal questions in addition to the criminal ones for which that record was created. This is the importance of the so-called Mueller report, which Barr described Friday as “a ‘confidential report explaining the prosecution or declination decisions’ he has reached, as required by 28 C.F.R. § 600.8(c).”

Mueller’s report is likely geared not toward telling a story or answering non-criminal questions but toward fulfilling the purpose of the regulation—that is, explaining his prosecutorial decisions. Unless Mueller understands his role especially grandly, the report is likely not designed to fill the oversight shoes of Congress or to assist the legislature’s role in the impeachment process. Yet unless the report is particularly spare in factual detail, that will not stop politicians and commentators from redeploying it for all of sorts of other purposes.

This business of redeploying criminal investigative work product for purposes of history, for purposes of non-criminal accountability, for purposes of the public’s knowing the “truth” is dicey stuff. I wrote a book once about just how dicey it is and the perils of relying on prosecutors to play non-prosecutorial roles.

But here’s the thing: Having vested in an executive branch official the principal authority to investigate the president—having done so knowing that this official cannot indict the president, and thus knowing also that all he can do is “report” about him—the report becomes everything. It becomes the only mechanism by which you can figure out why the investigation is over. It becomes the central vehicle for the redeployment of the criminal probe for all of the other democratic purposes we have invested in that probe. At least as regards the president himself, one cannot then read much into the end of the investigation without reference to the text of the report. The report is the investigation and the investigation is the report.

If the Mueller report declares that there was, as a factual matter, no cause for concern about the relationship between President Trump and the Russian Federation, I will accept that finding. If it declares that the evidence of an untoward relationship between Trump world and Russia is insufficient to justify criminal prosecution, I will accept that finding. If Mueller concludes that the president’s interactions with law enforcement were all within his Article II powers, I will confine my future criticisms of Trump on this score to the normative acceptability of his conduct and accept the judgment that the criminal law has nothing to say about such presidential behavior. But to accept these conclusions, one needs to be in the same position that one is in at the end of a normal high-profile investigation. That is, one needs to know within a certain broad set of parameters not merely that the investigation has concluded but why.

We don’t know that yet. Until we do, the end of the Mueller investigation means very little—a great deal less than many people seem to imagine.