In reply to Andrew Willinger’s insightful post about judges undertaking historical research in applying the historical-analogical test set forth in NYSPRA v. Bruen, I would like to add a brief comment about the ethics of judges undertaking independent historical research, as opposed to their competence in doing so (not as legal experts, but as amateur historians). As Andrew pointed out, the Bruen opinion suggested the parties would submit whatever evidence they want about the historical pedigree of a challenged gun safety law, and judges could rely on the evidence submitted, as is typical in the adversarial process. In response, some judges have queried whether the court, or the parties, should recruit qualified experts to weigh in on each case, while other judges have seemingly undertaken their own independent historical research.
In 2017, the ABA published Formal Ethics Opinion 17-478. The opinion concluded that it violates the Code of Judicial Ethics for judges or their clerks to conduct independent factual research, including via the Internet. As the ABA summarized in the opening abstract for Opinion 17-478,
Easy access to a vast amount of information available on the Internet exposes judges to potential ethical problems. Judges risk violating the Model Code of Judicial Conduct by searching the Internet for information related to participants or facts in a proceeding. Independent investigation of adjudicative facts generally is prohibited unless the information is properly subject to judicial notice. The restriction on independent investigation includes individuals subject to the judge’s direction and control.
In this ethics opinion, the ABA was primarily clarifying the scope of Model Rule 2.9(C) of the Code of Judicial Ethics, which states: “A judge shall not investigate facts in a matter independently, and shall consider only the evidence presented and any facts that may properly be judicially noticed.” The accompanying Comment  to Rule 2.9 explains that the “prohibition against a judge investigating the facts in a matter extends to information available in all mediums, including electronic.” The ABA’s 2017 ethics opinion on this issue was apparently a response to a controversy set off two years earlier by Judge Richard Posner, then on the 7th Circuit, who in some published opinions cited his own Google research explicitly (see here and here and here). Judge Posner had also encouraged judges to do their own Internet research in his 2013 book Reflections on Judging. Around 2017 or 2018, the Multistate Professional Responsibility Exam (MPRE) began including questions about judges doing independent factual research.
Of course, judges and their clerks may undertake their own legal research, which includes using electronic databases like Westlaw or Lexis to search for case law, statutes, and regulations, including old laws and cases. The prohibition applies to independent factual research by judges and judicial clerks. The ethics opinion also explains, in detail, that judges may take judicial notice of non-adjudicative facts – facts not in dispute as part of the litigation.
Footnote 9 of Formal Opinion 17-478 says that, as of the date of publication (Dec. 8, 2017), “[t]hirty-one states have adopted Model Rule 2.9(C) or language substantially similar in their judicial codes. There is no similar provision in the Code of Conduct for United States Judges.” Even in the 19 states that have not yet formally adopted the ABA’s Code of Judicial Conduct, the Code operates as highly persuasive authority for many judges and state disciplinary authorities.
Although the ABA’s Code of Judicial Conduct does not apply to federal judges, Canon 3(A)(4) of the Code of Conduct for United States Judges corresponds closely to Model Rule 2.9(A) in the ABA’s Model Code of Judicial Conduct, covering ex parte communications. Formal Ethics Opinion 17-478 discusses Rule 2.9(A) and suggests that independent factual research by judges also constitutes a form of ex parte communication, thereby violating 2.9(A) (more precisely, Opinion 17-478 then proceeds to say that Rule 2.9(C)’s ban on independent factual research is included in the ex parte rule of Rule 2.9(A)). Note that the Code of Conduct for United States Judges does not apply to the U.S. Supreme Court, at least traditionally.
Bruen thus presents a potential ethical problem for state judges under Model Rule 2.9(C) of the ABA Code of Judicial Conduct, and arguably for federal judges under Canon 3(A)(4) of their Code. It is appropriate (that is, not an ethical violation) for judges to research old historical statutes or cases to determine the historical pedigree (or analogs) of certain laws. But it arguably could be an ethical violation for Judge Benitez to use the Winchester Firearms website to determine a historical fact about what arms were in circulation among civilians in the nineteenth century—a course of action the judge suggested at a recent court conference.
What about judges reading law review articles about the historical basis for gun laws? Formal Opinion 17-478 discusses judges reading articles, but the question of historical facts is not discussed. It appears, based on the discussion of article research, that it would be appropriate for a judge to read law review articles to learn about the historical laws or cases, but not to learn what types of guns were in circulation at earlier times in history, what percentage of the public owned guns or carried guns in public, or what the public believed about guns or gun ownership. Another question likely to come up in the Second Amendment context is the role of amicus briefs, such as those submitted by historians and other academics. The ABA did not address amicus briefs in its Formal Opinion, but presumably these do not present the same ethical concerns, because the parties have notice about the filing of amicus briefs and have the opportunity to respond to any arguments that amici raise.
A closing caveat: I am not aware of any judges facing disciplinary actions for conducting independent factual research in violation of Model Rule 2.9(C). It is important to remember that enforcement of the rules of judicial ethics requires someone in the proper position of authority to initiate an enforcement action, and there is a large element of discretion and willpower here. I should also add that I have not seen any recent empirical studies or anecdotes about how many judges violate the rule or comply with it.