Special Counsel Robert Mueller held a press conference this week to wrap up his investigation of Russian interference in the 2016 presidential election and to clarify his position on whether the President obstructed justice. “[I]f we had confidence that the President clearly did not commit a crime, we would have said that. We did not, however, make a determination as to whether the President did commit a crime.” Which, obviously, inquiring minds want to know. Mueller explained that his hands were tied; he could neither seek an indictment, nor opine that the President’s conduct was indictable (based on probable cause to believe he committed a crime coupled with sufficient admissible evidence to obtain a conviction). Why? Because according to longstanding and binding Department of Justice policy, a President may not constitutionally be prosecuted or even secretly indicted for committing a federal crime until he leaves office.

Mueller was half-right; he was bound by DOJ policy not to indict. But the further decision not to opine was all his. And if he is subpoenaed to testify before Congress, a strong argument can be made that he can, and should, say more.

A 2000 DOJ Opinion, on which I worked while I was a deputy in the Office of Legal Counsel, reaffirmed a Watergate-era DOJ determination that criminally prosecuting a sitting President would violate the constitutional principle of separation of powers, even after the Supreme Court decided in Clinton v. Jones that filing a civil suit would not. This is because “criminal prosecution . . . would unduly interfere with the ability of the executive branch to perform its constitutionally assigned duties.” Few constitutional law experts take issue with that conclusion. Somewhat more controversially, the 2000 DOJ Opinion reaffirmed the “better view” that a sitting President is immune from criminal indictment, even were actual prosecution to await the end of the President’s term. Indictment alone could distract and stigmatize the President, creating a “Russian roulette” scenario (how fitting!) during which the President’s effective “power to govern” might be threatened. Third, and even more controversially, the Opinion explained in a footnote that even a sealed indictment is a no-no; the risk of a leak “take[s] an unacceptable gamble with fundamental constitutional values.” The various public interests on the other side are, on balance, insufficient to justify the potential interference with the President’s assigned constitutional duties.

Reasonable people can (and do) reasonably take issue with the second and especially third conclusion barring public and secret indictments, particularly where the crime’s applicable statute of limitations might run before the President becomes indictable. The 2000 Opinion concluded that, on balance, the concerns raised by an in-term indictment outweigh the interest in meeting a limitations deadline, especially where criminal courts or Congress might toll the limitations period under these unique circumstances. But, as with many separation of powers determinations, these judgments turn on contestable assessments of competing norms and interests alongside predictions about effective governance. Perhaps the truly better “better view” is that, at least in particularly compelling circumstances and where necessary to meet the limitations period, a President could be offered a choice between indictment under seal now and waiving a limitations-based defense for a post-presidential-term indictment.

By comparison, no one controverts the 2000 OLC Opinion’s conclusion, as recounted by Mueller, that the Constitution “permits the investigation of a sitting President because it is important to preserve evidence while memories are fresh and documents are available,” and such evidence may be used to charge non-immune defendants (as Mueller repeatedly did here). But in Mueller’s view, investigate is all he could do vis-à-vis the President. He added: “And beyond Department policy, we were guided by principles of fairness. It would be unfair to potentially accuse somebody of a crime when there can be no court resolution of an actual charge.” So: “[T]hat was the Justice Department policy and those were the principles under which we operated. From them we concluded that we would not reach a determination―one way or the other―about whether the President committed a crime.”

In my view, that conclusion is perfectly respectable. One can reasonably extend the OLC argument for precluding indictments to also disfavor a formal announcement that a federal prosecutor would have sought an indictment but for constitutional immunity; like the former, the latter also might place the President under a cloud of “stigma and opprobrium.” Indeed, even outside of this especially sensitive context, the DOJ Manual’s “Principles of Federal Prosecution” disfavor naming unindicted co-conspirators in the “absence of significant justification” because they similarly have no legal forum in which to clear their names. And the suggestion that the regulation instructing the Special Counsel to “explain[ ] the prosecution or declination decisions reached” required him to issue a binary go/no-go recommendation gives short shrift to the Manual’s Principles stating that prosecutors might forgo indictment for various non-merits-based reasons.

Of course, to some extent the mere amassing and public assessment of evidence to preserve it and to pursue other wrongdoers creates a similar cloud. Even without any final conclusions of culpability, Mueller’s report is replete with evidence showing that President Trump engaged in misconduct, whether provably criminal or not. And let’s not forget the indictment and plea agreement of Trump’s former personal lawyer Michael Cohen, which proclaimed that Cohen paid hush money “at the direction of a candidate for public office”―unidentified, but in context clearly referring to Trump―to forestall public allegations that Trump engaged in two extramarital affairs. In the end, separation of powers reasoning relies on nuance and balance, and the distinctions between issuing a suspended indictment, and saying one would indict absent immunity, and presenting a pretty damning just-the-facts ma’am report are fine indeed.

But my broader point is this: Mueller’s determination that he could pursue only the just-the-facts approach reflects an extension of the OLC Opinion’s reasoning rather than application of its edicts. The Opinion just doesn’t address this question, and even Mueller acknowledged that his articulated fairness concern went “beyond Department policy.” Mueller owns this judgment call.

Indeed, Attorney General William Barr, to whom Mueller ultimately reported, subsequently announced that he disagreed with Mueller’s view. While initially summarizing the report, Barr explained that he and Mueller’s earlier boss Deputy Attorney General Rod Rosenstein had expected Mueller to assess the evidence and then offer a prosecute-or-not recommendation. And just yesterday, Barr repeated his view that Mueller “could’ve reached a decision as to whether [the President’s conduct] was criminal activity.” On the surface, Barr’s statement might even be taken as reflecting a gloss on official DOJ policy―after all, Barr’s in charge now―that a public statement about indictability is appropriate and expected, let alone permitted by the 2000 OLC Opinion.

Okay, perhaps that’s a stretch. After all, had Mueller concluded that Trump’s misconduct would ordinarily merit indictment, maybe Barr would have then embraced Mueller’s reticence and refused to make the report public, or at least excised that recommendation before so doing. (One wonders whether Mueller went the facts-sans-recommendation route precisely to avoid inviting this response. One also wonders why Barr, if he was truly surprised and dismayed by the lack of a go/no-go recommendation, didn’t “remand” the report and ask Mueller to add one.) But given that Barr had already committed to release as much of the report as possible, it seems at least somewhat jarring that Barr would openly question Mueller for withholding a bottom line recommendation if Barr truly believed that publicly revealing a go recommendation―or even risking that a non-disclosed go recommendation could be leaked (as happened with the Watergate grand jury’s indictment listing President Richard Nixon as an unindicted co-conspirator)―would be unconstitutional under the 2000 OLC Opinion. Barr would have found it exceedingly difficult to explain publicly why he couldn’t release Mueller’s findings on obstruction, without revealing the very thing he believed couldn’t constitutionally be revealed. This at least strongly suggests that Barr doesn’t read the Opinion to preclude Mueller from publicly announcing that the President committed an indictable offense, so long as nothing more tangible follows.

Of course, this woulda/coulda thinking is water under the bridge. But the point still matters for the future shoulda. It means Mueller is not barred going forward from publicly opining as a private citizen whether he believes Trump committed indictable offenses, especially if asked to do so under oath by the House of Representatives as it considers whether and how to respond to the report.

Any future clarification would come from Mueller as a private citizen rather than as a federal prosecutor, freeing him from the Department’s policy constraints whatever they may be. Both former FBI Director James Comey and over 900 former federal prosecutors (from both Democratic and Republican administrations) have proclaimed that the misconduct Mueller describes would normally warrant indictment, and to my knowledge no one has criticized them for failure to respect the DOJ policies that previously guided their official actions. That said, Mueller’s private citizen status might attenuate his articulated fairness concerns only marginally, as the general public might still “hear” him as the prosecutor rather than as a private commentator.

The more important point is that Mueller should feel some obligation to assist Congress, if asked, with the sound exercise of its own constitutional responsibilities of oversight and impeachment. As the 2000 OLC Opinion explained, and Mueller himself reminded, “the Constitution requires a process other than the criminal justice system to formally accuse a sitting President of wrongdoing.” The fact that the authority for censuring or removing a sitting President for criminal (or other) misconduct lies with Congress rather than the Executive Branch shouldn’t hermetically seal the latter’s knowledge from the former.

Now, Mueller made clear in the press conference that he has no desire to dish―“I would not provide information beyond that which is already public in any appearance before Congress”―whether to avoid casting any cloud; to avoid contradicting Barr’s formal conclusion that the evidence would not support indictment, immunity aside; or simply to avoid appearing to take a political side. But if subpoenaed to testify under oath, his personal desires are of no moment. While refusing to answer congressional questions directly, or even at all, has recently been honed to an art form, “I don’t wanna” isn’t really an acceptable response absent a legitimate claim of privilege. One can debate whether executive or attorney-client privilege might yet attach to redacted portions of the report or the unseen evidence underlying it. But the report’s public release almost surely waived any such privilege with respect to the revealed information. So suppose Mueller is carefully asked this: “In your opinion as you sit here today, based solely on the information presented in the now-public report, does the report describe misconduct that would merit indictment under conventional prosecutorial standards but for presidential immunity?” I understand Mueller’s “I don’t wanna” inclination, but I believe his public servant ethos should dictate a different answer. Especially if he testifies behind closed doors.

Of course Congress may impeach a President for grave misconduct that doesn’t include an indictable crime. And here, that’s where the real action may lie. So Mueller might assist Congress’s consideration simply by redescribing and giving context to the underlying conduct presented in the report―especially as many members may be more familiar with the report’s conclusions than its detailed content. But at the same time, as Congress might appropriately give appreciable weight to actual criminal behavior, helping Congress form a judgment about such is particularly useful.

I don’t mean to prejudge Mueller’s honest take. Mueller might believe that Trump’s misconduct would merit indictment absent immunity. Or Mueller might believe that similar behavior by a non-President would merit indictment, but Trump’s behavior would not, perhaps because establishing corrupt intent is more difficult where the ostensibly obstructing behavior dovetails with the apparent exercise of Article II powers, or perhaps because the bar in general ought to be higher for Presidents. Or Mueller might believe that the described misconduct wouldn’t merit indictment even under a normal-citizen standard, even though he clearly determined that the evidence didn’t exonerate the President. Or Mueller might believe that some of the described misconduct falls into each of these categories. At this point, we just don’t know.

But perhaps in the near future we, or at least Congress, should know. And if we don’t, that’s on Mueller alone.