[Cross-posted at Lawfare.]

The possibility that Special Counsel Robert Mueller might issue a subpoena to President Trump to compel him to testify before a federal grand jury has, understandably, provoked questions: Can the President be forced to testify if he refuses to give Mueller an interview voluntarily? What has the Supreme Court said on the subject? And if the staring match between Team Trump and Team Mueller becomes litigation, who is likely to win?

The bottom line, in our view, is that Mueller would probably prevail if and when a battle over a grand-jury subpoena makes its way into court. But it is not a sure thing, and the President has plausible arguments available to him that a court would have to work through before enforcing a subpoena for his testimony.

By far the most important precedent here is United States v. Nixon—the landmark 1974 Supreme Court decision in which an 8-0 Court held that President Nixon could be forced to comply with a subpoena to produce some of the previously undisclosed “Watergate tapes” to Special Prosecutor Leon Jaworski. Jaworksi sought to use the tapes as evidence in the criminal case against the so-called “Watergate seven” (a case in which Nixon himself was an unindicted co-conspirator). Nixon has some caveats (more on these below), but its analytical framework is the starting point for any discussion of a subpoena to the President.

That analytical framework treats the validity of the subpoena on its face as a separate question from whether the President might have a case-specific reason to seek to quash it. Thus, Part III of Chief Justice Burger’s opinion for the Court focused solely on whether the subpoena was facially valid—an analysis that turned on the three requirements of Rule 17(c) of the Federal Rules of Criminal Procedure, i.e., that the subpoena seek specific, relevant, and admissible evidence from the recipient. As the Court explained, “where a subpoena is directed to a President of the United States,” courts, “in deference to a coordinate branch of Government, should be particularly meticulous to ensure that the standards of Rule 17(c) have been correctly applied.” But if those standards were met, the fact that the recipient was the President of the United States was not, on its face, a reason to quash the subpoena.

Instead, in Part IV of the opinion, the Court turned to whether the President could invoke a specific defense against enforcement. And although the Court agreed with President Nixon that the Constitution recognizes an “executive privilege” against disclosure of confidential, internal Executive Branch communications, it nevertheless held that such a privilege was not absolute. Instead, the Court famously concluded that the privilege was overcome in Nixon’s case by “the fundamental demands of due process of law in the fair administration of criminal justice. The generalized assertion of privilege must yield to the demonstrated, specific need for evidence in a pending criminal trial.” Given that the party requesting the evidence in Nixon was the prosecutor, not the defendant, this holding necessarily took a rather dim view of the strength of an executive privilege claim in the face of a valid subpoena.

The rest, of course, was history. President Nixon ended up complying with the subpoena and turning over the tapes—which sealed his political fate. Just over two weeks after the Supreme Court ruled, Nixon resigned to ward off his near-certain impeachment and removal.

The subpoena Mueller would issue here differs in a potentially important respects from the one at issue in Nixon. The most important difference is that a Mueller subpoena would demand not material like the tapes or documents for use at a trial, but testimony from the President before a grand jury. That is, it would be a subpoena for the President to personally appear and give testimony, as opposed to produce documentary evidence. And it would be testimony at an earlier stage in the proceedings—before the grand jury, rather than subsequent to the return of a grand jury indictment.

Would either of these likely lead the federal courts today to reach a different conclusion? It’s certainly possible, but count us skeptical.

The forum question seems like an easy one. It is certainly true that a grand jury subpoena is different from a subpoena in conjunction with a criminal trial. But it’s not clear at all that those differences militate in favor of the recipient of the grand jury subpoena; the courts have, in fact, suggested the opposite. As the Supreme Court explained in United States v. R Enterprises in 1991, “The multifactor test announced in Nixon would invite procedural delays and detours while courts evaluate the relevancy and admissibility of documents sought by a particular subpoena. We have expressly stated that grand jury proceedings should be free of such delays,” and so “the Nixon standard does not apply in the context of grand jury proceedings.” Instead, under R Enterprises, “the motion to quash must be denied unless the district court determines that there is no reasonable possibility that the category of materials the Government seeks will produce information relevant to the general subject of the grand jury’s investigation.”

The stronger argument on behalf on Trump, in our view, would be that demanding testimony in person is meaningfully distinct from demanding the production of requested documents. But it’s not clear that the legal distinction would favor a sitting President. For starters, whereas a subpoena for specific documents could be met by a litigation-inducing claim of executive (or state secrets) privilege, a subpoena for testimony cannot be, because it won’t be the case that the answer to every conceivable question is protected by the privilege. Among other things, executive privilege doesn’t apply to conduct predating the President’s time in office, and it also could not be used to decline to answer questions about matters on the public record. At most executive privilege could be used to decline to answer specific questions, not to refuse to testify at all.

Of course, the President, like any witness, is entitled to invoke his Fifth Amendment privilege against self-incrimination. But leaving aside the (monumental) political implications of such a move, it is also not an absolute bar to being called to testify—though it often functions that way in practice. At least theoretically, the Fifth Amendment does not preclude a subject from appearing before a grand jury. It merely provides a basis to decline to answer specific questions—a right to remain silent. In any event, the Special Counsel, like any prosecutor, can overcome an invocation of the Fifth Amendment privilege by providing the President with “use and derivative use immunity”—that is, by immunizing him against the use of his testimony and any evidence derived from it to prosecute him.

The President could plausibly rely upon a new argument as well—that having to take time from his duties to sit before a grand jury (as opposed to producing physical evidence in his custody) would interfere with his Article II authority on a more general basis. Indeed, an 1818 opinion by Attorney General Wirt (quoted in a 2000 OLC opinion) suggested that, “[a] subpoena ad testificandum may I think be properly awarded to the President of the U.S. But if the presence of the chief magistrate be required at the seat of government by his official duties, I think those duties paramount to any claim which an individual can have upon him, and that his personal attendance on the court from which the summons proceeds ought to be, and must, of necessity, be dispensed with.” Modern travel aside, those concerns seem far less serious to us when the subpoena asks the President to testify in “the seat of government.”

The more serious problem with this argument is that it is suspiciously like the one the court rejected unanimously in Clinton v. Jones, in which the Court concluded that a sitting President is not absolutely immune from civil litigation for conduct that took place before he became President. Bill Clinton, in that case, argued that forcing a sitting president to answer a civil complaint would unduly distract him from his duties as president. In the course of reviewing the relevant precedents, Justice Stevens offered the following observations:

it is . . . settled that the President is subject to judicial process in appropriate circumstances. Although Thomas Jefferson apparently thought otherwise, Chief Justice Marshall, when presiding in the treason trial of Aaron Burr, ruled that a subpoena duces tecum could be directed to the President. We unequivocally and emphatically endorsed Marshall’s position when we held that President Nixon was obligated to comply with a subpoena commanding him to produce certain tape recordings of his conversations with his aides. . . . Sitting Presidents have responded to court orders to provide testimony and other information with sufficient frequency that such interactions between the Judicial and Executive Branches can scarcely be thought a novelty. President Monroe responded to written interrogatories, President Nixon—as noted above—produced tapes in response to a subpoena duces tecum, President Ford complied with an order to give a deposition in a criminal trial, and President Clinton has twice given videotaped testimony in criminal proceedings. Moreover, sitting Presidents have also voluntarily complied with judicial requests for testimony. President Grant gave a lengthy deposition in a criminal case under such circumstances, and President Carter similarly gave videotaped testimony for use at a criminal trial.

In the end, Justice Stevens concluded that the burden on the presidency of having to answer a civil complaint from a mere individual citizen was not so great as to require immunity:

Although scheduling problems may arise, there is no reason to assume that the district courts will be either unable to accommodate the President’s needs or unfaithful to the tradition—especially in matters involving national security—of giving “the utmost deference to Presidential responsibilities.” Several Presidents, including [Clinton], have given testimony without jeopardizing the Nation’s security. In short, we have confidence in the ability of our federal judges to deal with . . . these concerns.

The “interference” arising from a specific grand jury demand for testimony is arguably less serious than the interference of being generally subject to civil litigation from anyone who serves the president with a complaint. Moreover, the interests of the grand jury are generally regarded as far weightier than the interests of any private civil litigant. It’s hard to see how the courts could contend that the President must answer a civil complaint from Paula Jones but then contend that he need not answer a criminal investigative subpoena from a grand jury issued at the behest of the United States Department of Justice.

It’s possible, of course, that new concerns might arise that haven’t been addressed by these decisions. It is also possible that the current Supreme Court, which includes only four of the Justices who heard Clinton, would see matters differently. But based on the law as it stands today, we think it unlikely that the the President could successfully oppose a facially valid subpoena for grand jury testimony.

The President, of course, could refuse to comply with a subpoena even after it has been upheld by the Supreme Court. As the story goes, President Nixon seriously contemplated such a course after the Supreme Court ruled against him in July 1974. In such a circumstance, the ultimate question would not be up to the courts, but rather to Congress. Nixon eventually concluded that defying the Supreme Court would only hasten his impeachment. Whatever else may be said about the law and politics of such a confrontation, we hope we never have to find out whether the current President would see things the same way.

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