[Editor’s note: Originally published on May 16, 2019, this piece has been updated to include Reader’s suggestions of additional questions for the special counsel.]

Robert Mueller’s time as special counsel investigating Russian interference in the 2016 U.S. presidential election and links to the Trump campaign was notable for many things, among those his silence. Even as President Donald Trump talked and tweeted repeatedly about Mueller personally, the special counsel team, and their work, and even as the media covered Mueller’s every coming and going, Mueller let his work speak for itself.

That’s about to change. While the date hasn’t been set yet, odds are that Mueller will testify soon on the Hill. The three of us previously offered questions for Congress to pose to Attorney General William Barr when he testified before Congress. We now suggest the questions below for Congress to ask Special Counsel Mueller as he breaks his silence and offers congressional testimony. We offer these questions as an addition to the 60 questions posed by the 10 Democratic members of the Senate Judiciary Committee. We believe there is very little overlap between the two lists, and we offer ours as a supplement.

We encourage readers to add to our list with questions of their own (by sending their suggestions to lte@justsecurity.org). We will add readers’ questions to the list with attribution, but let us know if you prefer anonymity.

I. Process

1. Before you submitted your report on March 22, 2019, did Attorney General William Barr or Rod Rosenstein inform you that they believed you had the authority or the responsibility to bring an indictment against the President if you concluded there was sufficient evidence to establish the President committed a crime? Did Mr. Barr or Mr. Rosenstein inform you that they believed you should indicate in your final report whether you would have brought an indictment of the President were it not for the Justice Department’s preexisting view that a sitting President cannot be indicted?

2. If you knew before you submitted your report on March 22, 2019 that, according to the Attorney General of the United States, you could and should indicate that a sitting President had acted criminally if you concluded that the President had indeed engaged in a crime, would you have included that determination in your report if you considered the evidence supported it?

3. Upon concluding your work and submitting your final report, did you anticipate the Attorney General reaching and publicly announcing a conclusion on whether the President had obstructed justice? Would you have recommended that the Attorney General do so?

4. Were you ever concerned that William Barr, Rod Rosenstein, or Matthew Whitaker were improperly sharing information about your ongoing investigation with the White House?

5. Your report states:

“On March 9, 2017, Comey briefed the ‘Gang of Eight’ congressional leaders about the FBI’s investigation of Russian interference, including an identification of the principal U.S. subjects of the investigation. … The week after Comey’s briefing, the White House Counsel’s Office was in contact with SSCI Chairman Senator Richard Burr about the Russia investigations and appears to have received information about the status of the FBI investigation.”

Were you concerned that Sen. Burr improperly provided information to the White House about the status of the investigation? Did you raise these concerns with Sen. Burr or his staff?

6. On April 9, 2019, Rep. Charlie Crist asked Attorney General Barr the following question:

“Reports have emerged recently, General, that members of the special counsel’s team are frustrated at some level with the limited information included in your March 24th letter, that it does not adequately or accurately, necessarily, portray the report’s findings. Do you know what they’re referencing with that?”

Did Attorney General Barr have knowledge what those reports were referencing? In your view, did your letter of March 27, 2019, to the Attorney General provide him with knowledge of what those reports were referencing?

7. Your March 27, 2019, letter to Attorney General Barr referenced an earlier letter you had already sent to Mr. Barr on March 25, 2019. How many letters or communications in writing did you send to Attorney General Barr raising concerns about either his 4-page letter dated March 24, 2019 or his decision not to release the summaries your Office apparently prepared for public release? Why send those letters?

8. Attorney General Barr’s letter to Congress on March 22, 2019, stated that there were no instances in which the Attorney General or Acting Attorney General rejected any proposed action by you. Is that statement accurate? Were there instances in which you did not propose an action primarily or in part because you believed the Attorney General or Acting Attorney General would not approve it? Does that include instances in which you believed they would not have approved it for reasons other than the preexisting Justice Department view that a sitting president cannot be indicted?

9. Attorney General Barr said that he offered you the opportunity to review his March 24, 2019 letter to Congress and you declined. Is that accurate? If so, why did you decline?

10. What role, if any, did Matthew Whitaker or Rod Rosenstein play in the decision of your office to make a public statement about the Buzzfeed report that claimed the President directed Michael Cohen to lie to Congress? Why did your office respond to this news report and not do so for many others? What are the material differences between what Cohen told Congress on February 27, 2019 about the President’s telling him to lie and what Buzzfeed reported?

11. Many commentators, including highly experienced former federal prosecutors, were surprised by the timing of your end of the investigation while relevant litigation was ongoing and significant actors such as Julian Assange and Roger Stone could still, at least conceivably, flip and cooperate with your investigation, thus potentially yielding new investigations and even prosecutions. Please explain fully your reasoning for bringing the investigation to a close when you did.

II. Counterintelligence analysis

12. Upon your appointment, did you review the case opening documentation for the counterintelligence investigation into Russian election interference, codenamed Crossfire Hurricane? Can you explain the basis for the opening of that investigation? Do you believe it was a properly predicated investigation?

13. Do you believe that Congress, including the Gang of Eight, has been adequately informed by your team and other parts of the intelligence community with respect to any counterintelligence assessments of Americans who may have been acting wittingly or unwittingly on behalf of the Russian government? Do you believe Congress, including the Gang of Eight, has been adequately informed by your team and other parts of the intelligence community with respect to other counterintelligence information that has come out of your and related investigations into Russian interference in the American political process and public and private institutions? If not, what have been the obstacles to Congress being adequately informed?

14. Did your office ever provide any assessment of the extent to which President Trump is acting—wittingly or unwittingly—to advance the interests of the Russian Government; if so, has that assessment been provided in some form to Congress (and, if so, to which Members)? If your office did not make that assessment, are you aware of the FBI or others in the government having produced such an assessment at any point, and do you know if that has been provided in some form to Congress? Are you aware of any consideration, in your office or elsewhere in the administration, of mitigation measures to address concerns of Russian influence (witting or unwitting) in the Trump White House? If so, what came of that consideration?

15. On March 20, 2017, then-FBI Director James Comey stated in a public congressional hearing:

“I have been authorized by the Department of Justice to confirm that the FBI, as part of our counterintelligence mission, is investigating the Russian government’s efforts to interfere in the 2016 presidential election and that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government.”

The May 17, 2017 Order establishing your mandate stated:

“The Special Counsel is authorized to conduct the investigation confirmed by then-FBI Director James B. Comey in testimony before the House Permanent Select Committee on Intelligence on March 20, 2017.”

Your report, however, suggests that the counterintelligence investigation may have been conducted by other parts of the Justice Department. Given the public statements made by the FBI Director and given the Justice Department’s order, please explain publicly whether you maintained control over the counterintelligence investigation and your role and relationship to it since you assumed the position of Special Counsel.

16. In your report, you note that your office considered whether to charge Carter Page under the Foreign Agents Registration Act for being an unregistered agent of Russia, but did not believe you had sufficient evidence to prove these charges beyond a reasonable doubt. You also indicate that Page was the subject of a FISA order, and that the FBI did meet the lower probable cause threshold for that order on four instances. Did you ever review the underlying materials for the FISA order? Would any of those materials have included the evidence you considered in deciding whether to charge Page criminally?

17. Are significant parts of the counterintelligence investigation, confirmed by then-FBI Director James Comey on March 20, 2017, still ongoing?

18. Over the entire course of your investigation, did you have unrestricted access to the FBI to direct the Bureau to pursue leads and other investigatory matters of interest? Did you have unrestricted access to the CIA to encourage similar efforts?

III. Obstruction

19. Volume 2 of your final report strongly indicates that, if President Trump engaged in criminal obstruction of justice, some of his personal lawyers were directly involved in those activities and could be criminally liable as well. What was your decision for not pursuing indictments of those lawyers for involvement in obstruction and witness tampering? Was your decision affected by the prospect of the President being included explicitly or implicitly as an unindicted co-conspirator?

20. Please describe your reasoning for including in your final report a comprehensive response to statutory and constitutional defenses to obstruction. It appears this reasoning would be relevant only in anticipation of an institution (such as Congress or future prosecutors) potentially pursuing criminal charges or other institutional actions (such as impeachment) against Mr. Trump during or after his presidency. Is that what you had in mind when including that response?

21. Your final report states:

“Although the events we investigated involved discrete acts …. it is important to view the President’s pattern of conduct as a whole. That pattern sheds light on the nature of the President’s acts and the inferences that can be drawn about his intent.”

Does that mean that a proper way to read the report is to consider not only whether each of the instances of potential interference independently constitutes a potential crime of obstruction but also whether the overall set of multiple instances (including, perhaps, instances that on their own would not suffice) would help to establish a case of criminal obstruction?

22. Your final report divides the actions and motives of the President in the potential case of obstruction into “two phases”:

“[T]he actions we investigated can be divided into two phases, reflecting a possible shift in the President’s motives. The first phase covered the period from the President’s first interactions with Comey through the President’s firing of Comey. During that time, the President had been repeatedly told he was not personally under investigation. Soon after the firing of Comey and the appointment of the Special Counsel, however, the President became aware that his own conduct was being investigated in an obstruction-of-justice inquiry. At that point, the President engaged in a second phase of conduct, involving public attacks on the investigation, non-public efforts to control it, and efforts in both public and private to encourage witnesses not to cooperate with the investigation” (Vol. II, p. 7).

Is it accurate to say that, in your view, the President’s actions in phase two—after he was aware that his own conduct was being investigated in an obstruction-of-justice inquiry—were motivated by a desire to interfere with investigation of his potential underlying crime of obstruction?

23. You indicate in your legal analysis for obstruction that even in the absence of an underlying crime, an erroneous belief that the underlying conduct was criminal, or even a desire to conceal embarrassing information from becoming public, could nevertheless constitute “corrupt” intent. Did any of the evidence you uncovered suggest that these kinds of motives may have been driving the President’s actions?

24. What is Congress’ constitutional basis for investigating obstruction of justice by the President, and how would such an investigation be consistent with the separation of powers?

IV. Conspiracy

25. Leading election law experts (including Bob Bauer, Rick Hasen, and Paul S. Ryan) have criticized how your final report describes existing campaign finance law and believe it improperly provides an opening for mischief in the future—for example, (a) by suggesting that the law is unclear on whether a foreign government’s providing essentially opposition research is “a thing of value” and (b) by suggesting “coordination” required an agreement between the Trump Campaign and the Russians to be criminal, despite the absence of such a requirement in federal campaign finance law. How do you respond to these criticisms?

26. Was the legal analysis for campaign finance law in your report a product solely of personnel in your Office or other parts of the Justice Department as well? If other parts of the Justice Department, what role did they play in informing the analysis or working on drafts of it?

27. Would it have been a crime for candidate Trump to promote Russian interests in shaping the Republican primaries and public discourse in the general election or in offering Putin relief from U.S. sanctions in exchange for a highly lucrative real estate deal in Moscow? Did you consider exploring those activities as a potential crime? If these are concerning but perhaps not criminal activities, would you recommend other forms of scrutiny so the public can better understand any such quid pro quo?

28. What is the burden of proof that the Justice Department must meet to prove criminal conspiracy, and how does the Justice Department approach this standard in terms of deciding whether to bring charges? Based on the evidence you uncovered in the course of investigating conspiracy, do you believe your evidence would be sufficient to meet a lower burden of proof, for example, the civil standard of “preponderance of the evidence”?

29. What are the most plausible explanations for Trump Campaign Chairman Paul Manafort’s repeatedly sharing internal polling data with Konstantin Kilimnik, a person the FBI assesses to have ties to Russian intelligence?

30. Your investigation was not able to establish, according to criminal law standards, whether George Papadopoulos informed the Trump campaign about the Russian government having derogatory information on Clinton in the form of emails and indications from the Russian government that it could assist the campaign through the anonymous release of information damaging to Clinton. Do you believe that it’s more likely than not that Papadopoulos did inform the campaign?

V. Next Steps

31. Overall, what did you anticipate happening next when you submitted your final report? In particular, what did you think Congress would do with your findings regarding obstruction of justice, given the detailed nature of your findings and your view that it would be improper to opine on whether those findings constituted the commission of criminal activity by a sitting president?

32. Based on your investigation, what legislative reforms do you think may be needed to stop ongoing or future foreign government interference in U.S. elections? Would you recommend a federal requirement for campaigns to report any offer of assistance from a foreign government agent, with failure punishable as a crime? Would you recommend codifying a federal offense for knowingly trafficking in stolen property (perhaps specifically in the campaign context, or perhaps not), to include hacked emails and other electronic documents and communications? Would you recommend expansion of federal offenses for aiding and abetting violations of the Computer Fraud and Abuse Act? Would you recommend changes or official clarifications of campaign finance law rules on foreign national contributions to political campaigns? Do you think Congress should look into the rules and enforcement of the Foreign Agents Registration Act and Lobbying Disclosure Act?

33. A provision of the Special Counsel regulations (28 CFR 600.4) provide for non-criminal remedies for wrongdoing discovered by the investigation. What, if any, such remedies did you consider might be appropriate? Did you make any recommendations to the Attorney General or Acting Attorney General under this provision?

34. If Congress wanted to determine for itself the strength of the case of obstruction or abuse of power, not necessarily according to criminal law standards of proof, who would be the most important potential witnesses for the public to hear from and for Congress to call on to testify?

35. What major investigative questions remain, and how would you recommend Congress playing a role in answering them?

Question from Reader (David Cay Johnston):

36. Did acting Attorney General Whitaker, Attorney General Barr or Deputy Attorney General Rosenstein ever suggest that you wrap up your investigation? Did you in anyway file the report of your investigation earlier than you felt was appropriate?

Question from Reader:

37. Please generally describe the criteria for assessing whether a US citizen is acting to advance the interest of a foreign government. Was Candidate Trump evaluated with these criteria before the election? What was that assessment? Were any assessments documented? If so, where are those documents? Were any other members of the Trump campaign, Trump Organization, or Trump family so evaluated? Please indicate whether there was any pre-election assessment of Paul Manafort as a foreign agent for the Russian Government.

Question from Reader (edited):

38. It has been reported that as a component of Moscow Tower, Trump organization was to offer Putin a very expensive penthouse. Was this investigated? Is there any documentation except for what is in Vol. 1? Would such an arrangement be legal?

Question from Reader:

39. Mueller was specifically asked to investigate any links between the Trump campaign and the Russian government, however, he was also asked to investigate Russian election interference more generally. It seems plausible that other campaigns besides Trumps might have been targets of Russian outreach. We’ve all seen the photo of Jill Stein, Putin and Mike Flynn at the RT gala. Did Mueller’s team investigate Stein or any of the other presidential campaigns for possible Russian connections?

Question from Reader (with light edits):

40. Why didn’t you resign as Special Counsel very soon after submitting your report to free you to testify as you wished without restraints from Attorney General Barr, the Justice Department, or the President?

Question from Reader (light edits):

41. Were violations of the Logan Act considered in any other regard outside of the Flynn investigation? Do you consider the Logan Act an enforceable law?

Question from Reader:

42. Did the office ever evaluate the polling data [that Manafort shared with Kilimnik, see #12 above] for Trump campaign strategy, whether the data assessed candidate Clinton’s potential weakness to Russian email releases? Did the office interview Tony Fabrizio about the polling data? What was the summary of such interviews?