It seems to me Judge Sullivan may have violated two of the Canons of Judicial Conduct, by (a) using a Washington Post op-ed as ex parte communication, and (b) commenting on a pending matter by filing a petition for en banc rehearing.
First, the ex parte communication. Why has nobody made a big deal of how Gleeson wrote a Washington Post op-ed suggesting e appoint an amicus and investigate the decision to dismiss charges, and then Judge Sullivan did exactly that and appointed Gleeson as the amicus? This was ex parte. A judge is supposed to do things with the input of the parties, and not give his ear to either party or anyone else outside the courtroom to decide what to do. Even an amicus has to apply to the court for permission to give input, and the parties can file their objections to that motion. The parties have a right to be heard. Ex parte influence is not only unlawful, but doing this kind of thing shows such a tin ear for judicial ethics that it really makes you wonder about Judge Sullivan’s competence and honesty both. Should someone file a complaint to some kind of judicial ethics board?


Later: Here’s what Canon 3(A)(4) of the Code of Conduct for United States Judges says:
A judge should accord to every person who has a legal interest in a
proceeding, and that person’s lawyer, the full right to be heard
according to law. Except as set out below, a judge should not
initiate, permit, or consider ex parte communications or consider
other communications concerning a pending or impending matter
that are made outside the presence of the parties or their lawyers.
If a judge receives an unauthorized ex parte communication
bearing on the substance of a matter, the judge should promptly
notify the parties of the subject matter of the communication and
allow the parties an opportunity to respond, if requested. A judge
may: 

(a) initiate, permit, or consider ex parte communications as
authorized by law;

(b) when circumstances require it, permit ex parte
communication for scheduling, administrative, or emergency
purposes, but only if the ex parte communication does not
address substantive matters and the judge reasonably
believes that no party will gain a procedural, substantive, or
tactical advantage as a result of the ex parte communication;

(c) obtain the written advice of a disinterested expert on the law,
but only after giving advance notice to the parties of the
person to be consulted and the subject matter of the advice
and affording the parties reasonable opportunity to object
and respond to the notice and to the advice received; or 

(d) with the consent of the parties, confer separately with the
parties and their counsel in an effort to mediate or settle
pending matters.
Second, there’s Judge Sullivan’s petition for an en banc rehearing of the mandamus petition. Attention has been focussed on how he is not a party to the Flynn case and so had no right to file an en banc petition. That is correct, but not important, since (a) maybe any person (say, you, reader!) can file such a petition, including Sullivan, and (b) it doesn’t matter in any case, because the Court can act sua sponte and order an en banc rehearing on its own without any petition, which is what they did. What *is* important is the impropriety of a judge filing a petition for rehearing en banc. It is evidence of bias and on its face it violates the canons of judicial ethics, in the same way as if he wrote up his complaint as an op-ed in the New York Times. Specifically, Sullivan’s en banc mandamus petition may violate Canon 3(A)(6). Canon 3(A)(6) says:
(6) A judge should not make public comment on the merits of a matter
pending or impending in any court. A judge should require similar
restraint by court personnel subject to the judge’s direction and
control. The prohibition on public comment on the merits does not
extend to public statements made in the course of the judge’s
official duties, to explanations of court procedures, or to scholarly
presentations made for purposes of legal education.
“But he was just defending himself,” you may say. “And he already had made his position known in the proceedings before the mandamus panel!” The mandamus panel was different. The appeals panel *ordered* him to respond— not “requested”, as they did with the Department of Justice. That overrides the Canon. They ordered him in the same way as they’d order a witness to speak. If a judge observes a murder being committed, a court can order him to testify at the murder trial and he not only can, but must, comment on that pending judicial matter. For In re Flynn, Judge Sullivan was not a party, everyone now agrees, including Sullivan’s lawyer (though on Twitter for a while there was a lot of controversy on that point). He could voice his thoughts only because he was ordered to by a court. But no court ordered him to file a petition for rehearing en banc. And he has no legal entitlement to file such a petition. It was just a document he published, with his comments on a pending judicial matter.
The Rules for Judicial-Conduct and Judicial-Disability Proceedings specify the procedures for investigation of ethical violations by federal judges.
Rule 7(a)(1) says:


a complaint against a judge of a United States court of
appeals, a United States district court, a United States
bankruptcy court, or a United States magistrate judge must be
filed with the circuit clerk in the jurisdiction in which the
subject judge holds office.
Rule 6, Filing of a Complaint, says:


(a) Form. A complainant may use the form reproduced in the Appendix
to these Rules or a form designated by the rules of the judicial
council in the circuit in which the complaint is filed. A complaint
form is also available on each court of appeals’ website or may be
obtained from the circuit clerk or any district court or bankruptcy
court within the circuit. A form is not necessary to file a complaint,
but the complaint must be written and must include the information
described in (b).

(b) Brief Statement of Facts. A complaint must contain a concise
statement that details the specific facts on which the claim of
misconduct or disability is based. The statement of facts should
include a description of:

(1) what happened;

(2) when and where the relevant events happened;

(3) any information that would help an investigator check the
facts; and 

(4) for an allegation of disability, any additional facts that form the
basis of that allegation.
For the DC Circuit, the form is here. It looks like it has to be mailed rather than emailed or filed on the web.
The DC Circuit Court of Appeals has a good FAQ on the process. FAQs: Filing a Judicial Conduct or Disability Complaint Against a Federal Judge, June 2016. Looking ahead:
If the circuit chief judge dismisses or concludes your complaint, you will receive a copy of the order and you will be notified of your right to have the circuit judicial council, consisting of circuit and district judges, (or national court, if applicable) review that order.


You must petition the judicial council within 42 days from the date of the circuit chief judge’s order.
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My August 17 comment at:
Friendly Fire: A Jurisdictional and Ethical Look at the D.C. Circuit’s Surprising Order that a Trial Judge Respond to a Legal Challenge to His Ruling by John Grimm and Amy Richardson, May 28, 2020:
I have an August blog post on this: Has Judge Sullivan Violated the Canons of Judicial Conduct? https://www.rasmusen.org/blog1/1594-2/ I’m trying to figure out whether to file a complaint. It would be about him, not the DC Circuit.


When the DC CIrcuit “ordered” Sullivan to respond, I, like everyone, took it as a slap in the face of Judge Sullivan. The DOJ was “invited” to respond. But now I see it differently: it was actually a friendly gesture towards Judge Sullivan. The canons of judicial conduct do not permit him to discuss cases except in special circumstances–such as being ordered to discuss them. So an “invitation” could be an invitation to violate the rules; an “order” gave him no leeway, so he’s free to talk.


On the other hand, his en banc petition was not ordered at all, or even requested, and he’s admitted at oral argument he’s not a “party”. Is it a violation?


The other canon is about ex parte communication. It sure looks like he read Gleeson in the Washington Post telling him to appoint an amicus, and then he appointed an amicus, without a chance for the parties themselves to brief whether he could. Is this a violation?


I think you authors are sympathetic to Judge S. but I’d value yours and all opinions before I go to the trouble of filing a formal complaint with Chief Judge Srinivasan. Maybe it isn’t as bad as it looks; I’m no expert.
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August 13 addition. I am seriously thinking of doing this. I could really use help. I owuld want to do it right— not just sending in the blog post below, which just asks the question of whether Judge Sullivan has violated the ethics rules, but sending in something like a brief that answers the question. This would require matching the two rules below against the specifics of what Judge Sullivan has done, as a first step, with lengthy cites from the Gleeson op-ed and the court proceedings, everything dated because the order is crucial. The second step would be analysis of whether the specifics means he has violated the rules, using their text, logic, and spirit. The third step would be to compare to previous similar actions of judges that have or have not been sanctioned, e.g., inviting Mr. Cassell in as an amicus because he was an expert on a particular legal topic, a mentioned in the oral argument. The fourth step would be to assemble a list of emails to which to send the complaint for publicity, since I think in this particular case, unlike many others (e.g., if a judge is getting senile), publicity is appropriate. This list would include not just media outlets but influential law professors and state court judges and retired federal judges.
If anybody wants to help, send me material. I can read very fast and I figure I can always throw it away (I will feel no obligation to use what you send), so don’t worry about the quality being low. If and when I get round to it, I will post my draft here. This would not be at all a secret or adversarial document. Indeed, I’m not sure I’m right about Judge Sullivan being in violation. One reader whose opinion I respect has already told me I’m off base, and I’m looking forward to talking with him once I get a draft of another project (village ostracism in Japan) cleared away. So if you think I’m wrong and want to persuade me, I’d very much like you to try.
And I might well conclude that on my own. A crucial part of the analysis section is to figure out the issue of when a judge can use outside reading, for example. I think it’s okay for a judge to read and rely on a case that neither party has discussed, for example, or to google for relevant facts— though wasn’t Judge Posner criticized for this at some point? But it’s definitely not okay for a judge to phone up an old friend and ask him for advice on a pending case. The Gleeson op-ed is somewhere in between. And I wonder whether, for example, it would be okay for Judge Srinivasan to read my blog posts and use those ideas in the present case.
As for Canon 3(A)(6) (not publicly discussing cases), the analysis is quite tricky. The mandamus panel “ordered” Judge Sullivan to respond and discuss Fokker, so his doing so in his panel brief was proper. This actually is a reason for them to “order” him to respond rather than “invite” him (as they did with the Justice Department). But Sullivan’s en banc petition was not in response to an order, and its discussions probably went beyond what was necessary in an en banc petition. As with Professor Hay’s 2020 defamation complaint against New York magazine or Bruce Reinhart’s Rule 11 motion in the Paul-Cassell/Jeffrey- Epstein/US-secret-deal case, there is the question of whether what is normally privileged by being in a legal filing goes too far and loses its protection. (With Hay, is he just trying to say bad thing about the magazine reporter; with Reinhart, were the plaintiffs saying bad thing about him as a nonparty that weren’t relevant to their pleadings. See “Bruce E. Reinhart’s Motion to Intervene or in the Alternative for a Sua Sponte Rule 11 Order (DE 79)”, case 08-80736-CIV-MARRA/JOHNSON (S.D. Florida, 2011) Jane Does #1 and #2 v. United States. Reinhart claimed that the plaintiffs had defamed him in their pleadings and should be punished for violating Rule 11 (docket entry 79).)
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