I have been meaning to blog about a new article by Dave Rapallo entitled House Rules: Congress and the Attorney-Client Privilege, 100 Wash. U. L. Rev. 455 (2022), which analyzes the Supreme Court’s dicta in Trump v. Mazars that recipients of congressional subpoenas “have long been understood” to retain common law privileges such as the attorney-client privilege. I commend Professor Rapallo’s article for its thorough analysis and defense of Congress’s historic position that it is not obligated to respect the attorney-client privilege or other privileges that stem from the common law, not the Constitution. Just this week his article was named the winner of the 2022 Levin Center Award for Excellence in Oversight Research (which also served as a reminder to me to post on this subject).
When the Mazars decision was announced, I pointed out that to the extent Chief Justice Roberts was commenting on what had “long been understood” by Congress, his observation was clearly wrong and not supported by the sole authority cited for the proposition, a 2003 CRS report by Louis Fisher. Contrary to the chief justice’s assertion, Congress has long asserted that it has discretion to decide whether to accept claims of common law privileges such as the attorney-client privilege. I therefore concluded (somewhat undiplomatically) that “the Supreme Court’s poorly researched dicta on this point should not be given any weight.”
Rapallo looks at the problem from two perspectives. The first addresses the substantive legal question whether Congress is bound to recognize the attorney-client privilege. He argues at length (persuasively in my view) that the general answer to this question is no. Drawing on separation of powers principles, legislative practice and precedent, and judicial authority, Rapallo demonstrates that acceptance of common law privileges is not constitutionally mandated and thus Congress’s decision to accept or reject the assertion of such privileges lies within its discretion and is not subject to judicial review.
The issue gets tricky, however, because the general practice of congressional committees is to respect valid assertions of attorney-client privilege. (Of course, as Rapallo points out, what constitutes a “valid” assertion of privilege can vary from jurisdiction to jurisdiction.) Thus, it can be argued that arbitrary rejections of attorney-client privilege are improper as a matter of congressional precedent (a kind of congressional common law, if you will), even if they are not a constitutional violation susceptible to judicial review. Furthermore, it seems to me that some breaches of the attorney-client privilege might rise to the level of a constitutional violation; imagine, for example, that a congressional committee sought to subpoena attorney-client communications in an ongoing civil or (even worse) criminal litigation.
This brings us to the second question addressed by Professor Rapallo, which is the proper interpretation of the chief justice’s remark in Mazars. As Rapallo shows, to the extent “[the chief justice] meant to suggest a broad consensus among Congress and the Judiciary that witnesses may defy congressional subpoenas based on the common law attorney-client privilege, that claim is simply wrong.”  In fact, “Congress has taken the opposite position for generations” and that position is reflected in numerous legislative materials, including many reports and legal opinions by the Congressional Research Service. [458, 471] The 2003 CRS report cited by the chief justice does not suggest otherwise, and therefore the Mazars dicta on its face appears both incorrect and perplexing. 
Rapallo recognizes, however, that simply declaring the chief justice to be wrong is disfavored and unsatisfying. He therefore considers alternatives. One is that the chief justice was declaring his view of what the law is or ought to be, and in effect directing the lower courts that henceforth they should view the attorney-client privilege (and other common law privileges) as binding on Congress. However, Rapallo (properly IMHO) discounts this explanation, noting that “there is little evidence that he intended to make such a remarkable pronouncement, unprompted and unbriefed.”  Put another way, this explanation would paint the chief justice as both sloppy and disingenuous, not necessarily an improvement over my original description of “poorly researched dicta.”
Instead, Rapallo embraces a different interpretation, namely that the Mazars language “could be read as acknowledging that recipients of congressional subpoenas retain the right to assert the privilege in other venues not directly related to congressional investigations and that complying with mandatory congressional demands does not constitute a general waiver in those other proceedings.” [458-59] (emphasis in original) He contends this interpretation fits better with the language of Mazars and comports with constitutional principles, legislative and judicial precedent, and actual congressional practice. [458-59] In particular, he points to the section of the CRS report cited in Mazars, which discusses an incident in the Senate Whitewater investigation where the committee claimed the right to, and did in fact, obtain certain attorney-client materials but agreed that the production of these materials would not constitute a waiver in other proceedings. [509-13] He also notes that the Mazars opinion separately describes this incident as part of its discussion of how the political branches have worked out disputes over information in the past and, as part of that discussion, directly acknowledges that the Whitewater committee in fact obtained the attorney-client materials after resolving the waiver issue.  Rapallo thus concludes that the “non-waiver” interpretation “directly aligns with the specific congressional investigation the Chief Justice highlighted (the Senate Whitewater investigation), is consistent with the only source he cited (the 2003 CRS report), and comports with separation of powers principles, congressional oversight precedent, and judicial rulings.” 
While it is difficult to say what the actual explanation for the Mazars dicta is, I agree with Professor Rapallo that “sloppiness” is not a useful explanation for lawyers trying to analyze the case and certainly not one that will be persuasive to the lower courts. On the other hand, I am not sure that the “non-waiver” theory is the best alternative explanation available. It does not fit well with the language used by the Court that recipients of congressional subpoenas “have long been understood to retain” their attorney-client and other common law privileges, which would be an awkward way of saying that recipients enjoy no such privileges in congressional investigations but may continue to assert them in unrelated proceedings. Furthermore, the language appears in a part of the opinion which purports to describe various “limitations” on congressional investigatory power, which suggests the right to assert privileges against a congressional subpoena itself.
A better explanation may be that the Mazars language refers to the fact that recipients of congressional subpoenas are understood to have the right to assertattorney-client privilege and that committees will consider such assertion as consistent with congressional rules and practice. This understanding is not necessarily inconsistent with the proposition that the scope and application of the privilege is ordinarily within the discretion of the committee and, ultimately, its legislative body.
Furthermore, this interpretation may have some relevance in the context of the Mazars case. In Mazars the Court found that a congressional subpoena for a president’s personal records required a careful balancing of the congressional interest in obtaining information with the executive interest in autonomy and avoiding undue burden on the sitting president. The Court may have believed that the fact congressional committees often must balance the need for information against other legal interests such as the attorney-client or executive privileges was supportive of its approach. In addition, while there was no specific discussion of the possibility the subpoenas involved in Mazars might infringe on attorney-client privilege, there seems little doubt the Court’s holding in Mazars would allow the judiciary to block a congressional subpoena for a president’s personal attorney-client communications.
This may explain why the January 6 select committee, when faced with a lawsuit by John Eastman, a personal attorney for former President Trump, chose not to argue that it could simply disregard Eastman’s claims of attorney-client privilege with regard to emails subpoenaed by the committee. Rapallo contends that the committee may have had practical and political reasons for contesting Eastman’s claims on the merits rather than relying on the controversial argument that congressional committees have the discretion to reject valid claims of attorney-client privilege. [497-500] That may be so, but it is also likely the committee realized such an argument would be looked on less favorably because of the solicitude for the president’s personal information reflected in the Mazars opinion.
If the significance of the Mazars dicta is limited to the unusual situation where a congressional committee seeks a president’s personal information, it will not affect most congressional investigations. However, if the Mazars framework is expanded to cover other types of information deemed worthy of special protection or if the courts develop a “Mazars-lite” approach to congressional subpoenas generally, committees may find their right to access materials allegedly protected by attorney-client privilege or other common law privileges repeatedly challenged in the courts. This is only one of the ways in which Mazars can be expected to shape future battles over congressional access to information.