Acting Attorney General Matthew Whitaker and Special Counsel Robert Mueller III (Photos by Diego Radzinschi)

President Donald Trump's decision to fire Attorney General Jeff Sessions was based on his view that Sessions had not adequately protected him from the investigation by Special Counsel Robert Mueller III. In his place, the president has installed as acting attorney general Matthew Whitaker who, we assume, the president expects will do a better job for him on that matter. But like so many of the president's efforts, this one has serious legal hurdles in the way.

To begin, there is no question that the Appointments Clause in Article II, Section 2 of the U.S. Constitution requires that the attorney general be nominated for that position and confirmed by the Senate if she or he is to carry out all the duties of that office. Whitaker has not been nominated for that position, let alone confirmed, and the president has shown no inclination to follow that path for Mr. Whitaker or anyone else at this time.

Second, there are a number of federal statutes that authorize the filling of vacancies in high positions, including the job of attorney general. Even if the administration prevails in its current battle with the state of Maryland and others on that issue, complying with those statutes does not eliminate the confirmation requirement which applies to positions, like that of attorney general, that must be filled by principal officers.

Last week's opinion from the Justice Department's Office of Legal Counsel argues that the history of prior acting appointments for high-ranking officers overcomes the constitutional objection, but all of its examples show only that the person was properly appointed and could execute some of the functions of the office. The problem is that, while some of what the attorney general does can be carried out by someone acting in that capacity, the most important matters much be handled by duly confirmed officers of the United States.

The general test, which was set forth in the 1976 decision in Buckley v. Valeo for members of the Federal Election Commission, is whether the appointee is exercising significant authority pursuant to the laws of the United States, including those having significant impact on the public. It is those acts of an attorney general that might end or limit the Mueller investigation that can only be done by a person who is an officer of the United States, which does not include Whitaker.

Here is how Whitaker may try to carry out the president's protection wishes and why it will not succeed as long as Mueller resists. Because Mueller's office was created pursuant to a regulation issued by a prior attorney general, not a statute, a duly confirmed attorney general could revoke the regulation and disband the office. That might mean ending all investigations, but even then, probably not the cases already filed or any grand jury indictments not yet made public. But because we do not know what Mueller has done to protect his investigations, we cannot be certain what precise effects it would have, but it would surely create a gigantic political explosion.

But with the Appointments Clause as his shield, Mueller should refuse to comply with such orders on the ground that they could only be issued by a duly confirmed attorney general, or by a duly confirmed deputy attorney general, Rod Rosenstein, who could constitutionally issue such orders but has chosen not to do so. Mueller might well have to go to court to vindicate his position, but given all that has happened to date, it is hard to imagine that he would slink off silently into the night and potentially have much of the work of his office destroyed.

In the alternative, Whitaker could fire Rosenstein, who has been acting attorney general and overseeing the Mueller investigation after Sessions recused himself because he was a potential witness. Following that path, Whitaker would then “re-assume” control over the Mueller investigation and take some or all of the steps outlined above. But like the prior scenario, this too would be met with the constitutional challenge that an unconfirmed Whitaker could not fire a confirmed Rosenstein, even though Whitaker had been named acting attorney general. After all, could the president make a sergeant an “acting general” and authorize him to usurp the powers of a general who had been duly confirmed by the Senate?

The president may counter with a claim that he could order Rosenstein to abolish the office and end the investigation, and fire him if he refused, and so he can accomplish the same end by authorizing Whitaker to carry out his wishes. While it is surely true that the president could fire Rosenstein for any reason, for no reason, or for an improper reason, that does not mean that the president can avoid taking the responsibility for the firing by having his designee do it for him. Moreover, as long as the regulation creating the Office of Special Counsel is in place, a special counsel can only be fired for good cause. If there is no such cause, a court would invalidate that attempted firing, no matter who ordered it. And, if the office is still intact, the investigations will continue.

All of this resistance depends on the willingness of Mueller and Rosenstein to refuse to align with Whitaker when he asserts powers that belong only to persons who have been confirmed by the Senate. The requirement of Senate confirmation is a vital check on presidential power, and what better time to rely on it than when the president is seeking to avoid Senate confirmation and thereby prevent a criminal investigation into alleged wrongdoing by him, his family, and his political supporters.

Alan B. Morrison teaches constitutional law at George Washington University Law School. He was the lead lawyer in Nader v. Bork in which Judge Gerhard Gesell of the U.S. District Court for the District of Columbia ruled that the firing of Archibald Cox as Watergate Independent Counsel violated the Justice Department regulation that created the office he headed.