Before the young year’s runaway news cycle galloped on to Trump’s stunning “s…hole” racism, reports that he paid off an adult film star during the campaign to cover up an affair, his repeated attacks on the media, his allegation that an FBI agent had committed treason, and the terrifying false ballistic missile alert in Hawaii, we paused for a smattering of stories speculating about a possible Mueller interview of Trump.

That’s speculation worthy of a pause. It is almost certain to happen in one forum or another before the investigation ends. The scope, timing, setting, and rules governing the interview will tell us a great deal.

Criminal investigations of substantial enterprises generally work from the smaller players toward the top in a hierarchical organization. The goal is to learn as much as possible from the little guys as they realize they are in legal jeopardy and see the value in talking. George Papadopoulos and, to a lesser extent, Michael Flynn are classic little guys who have been confronted with consequences and are now cooperating with the prosecution. It is unclear at this point how much Paul Manafort and Rick Gates, who have been indicted, are part of the bigger picture. Insofar as we know, neither is cooperating.

It will not be surprising if Mueller indicts – or at least exhausts the investigation of – more people before working his way to Trump. He and his team are likely to get only one session with Trump, which means they will want to know as much as possible before scheduling it. If Trump were a run-of-the-mill head of a criminal enterprise, he would be invited to talk with investigators, though Justice subpoenas targets to appear before grand juries only under limited circumstances. It is common practice and standard legal advice for grand jury targets to remain silent. They are entitled to do so by the Fifth Amendment, which gives each of us the right not to incriminate ourselves.

Presidents, however, are different. They, too, have to worry about incriminating themselves: a sitting president has never been indicted and Mueller is unlikely to break that precedent (incorporated in at least two Office of Legal Counsel opinions), but impeachment looms. Presidents, however, must also consider the political consequences of appearing uncooperative and the effect of their actions on the office of the presidency. And, while Mueller must try to get as much relevant information as possible from Trump, he must respect the office and recognize that presidents have many important things to do, including caring for that sizeable nuclear button.

Special and independent counsels, therefore, have negotiated accommodations. Gerald Ford was interviewed in the White House in the investigation into Lynette Fromme’s attempt to assassinate him. Ronald Reagan answered Iran/Contra questions under oath as president and twice after he left office. He also answered written questions from a grand jury. Clinton resisted testifying until he was served with a grand jury subpoena. His lawyers then negotiated limits; he testified with counsel present (unlike in a formal grand jury setting) for four hours by video from the White House and answered grand jurors’ questions. Special Counsel Patrick Fitzgerald interviewed George W. Bush in the White House for 70 minutes as part of the investigation into Valerie Plame Wilson’s blown CIA cover. Obama’s administration did not suffer a scandal worthy of a presidential interview.

Trump’s lawyers have floated the idea of submitting an affidavit or responding to written questions. Neither will be accepted. Investigators must meet in person with key witnesses in order to observe demeanor and tone of voice, as well as to be able to ask follow up questions to pin down the witness’s positions. Mueller, however, may be open to negotiating something short of Trump appearing in person before a grand jury.

This situation most closely resembles the Clinton experience. There, as here, the goal of the examination was to determine whether the President had participated in unlawful or impeachable conduct. Ideally, therefore, Mueller would want Trump to testify before the grand jury. Like Ken Starr, Mueller may be willing to allow the President to testify via video subject to a time limit. On the other hand, in the unlikely event that Mueller concludes that any wrongdoing likely does not reach Trump, he may settle for a less thorough and less intrusive session.

Under compelled questioning, Trump could – and from a legal defense standpoint probably should – take the Fifth, particularly given his demonstrated propensity to lie. Taking the Fifth could be politically damaging if the public learned of it. Despite repeated admonitions by courts to the contrary, the public commonly views assertion of the Fifth Amendment as a confession of guilt. Because grand jury proceedings are secret, however, word of his silence would be made public in the near term only if it leaked. Trump could divulge the fact, but it would be a felony for others in the process to reveal grand jury testimony. Similarly, the substance of an interview outside the grand jury would be private. Given Mueller’s tight ship, any news would likely come from Trump or his lawyers.

Assuming Trump decides to talk, he may state that he does “not recall” when asked incriminating questions. In doing so, he may avoid advancing the investigation and lessen, but not eliminate entirely, the likelihood of being held accountable for lying. Because deception is criminal only if it is intentional, prosecutors generally cannot prosecute a witness who does not recall, unless they can prove that he is lying about his recollection – no easy task. In any event, Trump is unlikely to be prosecuted criminally for false statements, but they could be relevant in impeachment proceedings.

Trump may also refuse to answer questions about his communications by asserting executive privilege. This doctrine recognizes the need to afford presidents and advisors confidentiality in discussing matters related to execution of the president’s duties. In U.S. v. Nixon, however, the case in which the Supreme Court first identified the constitutional grounding for the doctrine, it ordered Nixon to comply with a grand jury subpoena to turn over the Watergate tapes to Special Prosecutor Leon Jaworski. The Court held that the demand of a grand jury investigating possible criminal conduct overcame the privilege. Trump’s assertion of privilege likely would face the same fate.

Trump may try to negotiate limits on the topics that can be addressed. Mueller likely will agree to such limits only if he already has eliminated certain lines of investigation.

Finally, the timing of any questioning is unclear. While press stories made an interview sound imminent a couple of weeks ago, it is far more likely that the discussions are preliminary and Mueller has more fish to fry before he grills Trump.

Bill Yeomans is the Senior Justice Fellow at Alliance for Justice. He currently serves as Lecturer in Law at Columbia Law School, and previously taught constitutional law, civil rights, and legislation at American University Washington College of Law. He also served for 26 years in the Department of Justice, where he litigated cases involving voting rights and discrimination in employment, housing, and education, and prosecuted police officers and racially motivated violent offenders before assuming a series of management positions, including acting Assistant Attorney General. For three years, Bill served as Sen. Edward M. Kennedy’s chief counsel on the Senate Judiciary Committee, and has also held positions at AFJ and the American Constitution Society.