[Editor’s note from Ryan Goodman: I asked a foremost expert on legal ethics and professional responsibility, Stephen Gillers, to share with Just Security his views on Matthew Whitaker’s appointment as Acting Attorney General and, in particular, whether Whitaker should be able to oversee the Mueller investigation. Professor Gillers’ response follows.]

The media commentary surrounding the decision to put Matthew Whitaker in charge of the Mueller investigation is a bit muddled, as often happens when legal questions are suddenly thrust into the headlines. A critical distinction is needed between ethics and recusal.

Whitaker has repeatedly expressed hostility to any expansion of Mueller’s jurisdiction beyond the possibility of collusion between the Trump campaign and Russia. That includes expansion to investigate Trump family finances. A fair reading of his comments suggests that he also has doubts about the decision to appoint a special counsel at all.

This history raises two questions. First, can Whitaker oversee the Mueller probe as a matter of legal ethics? The answer to this question is easy. Yes. Or to put it another way, Whitaker could not be disciplined as a lawyer if he were to decide to substitute himself for Rod Rosenstein as the person to whom Mueller reports. Of course, this assumes that any decisions Whitaker makes as Mueller’s supervisor were within the broad but not unlimited scope of traditional prosecutorial discretion. He would obstruct justice if he quashed or crippled the Mueller investigation for the purpose of protecting Trump or for political advantage.

The second question is whether Whitaker’s stridently harsh comments about the special counsel’s work warrant his recusal from overseeing the Mueller probe. The question of recusal is not the same as the question of legal ethics. Nor should it be. The Department of Justice must be concerned not only with the ethical exercise of prosecutorial discretion in fact, but also with the public’s confidence in the exercise of that discretion. So conduct that would not be unethical may nonetheless require recusal. And that is true here.

Whitaker should be recused. His repeated expression of hostility to the Mueller investigation makes it impossible for the public to have confidence in his ability to exercise the necessary prosecutorial judgment in supervising Mueller. Bolstering that conclusion is the fact that his public comments on the special counsel’s work were uninformed. He condemned expansion of the Mueller investigation beyond possible collusion with Russia when he could not have known what evidence Mueller had uncovered, and on which Rosenstein may have relied, justifying any expansion. While Whitaker was free, of course, to speak despite his ignorance in this regard, his precipitous judgment further undermines the ability of the public to have confidence in the decisions he would make if he were allowed to supervise Mueller.