The end of Jeff Sessions' tenure as attorney general has implications not only for federal criminal justice policy but also the security of the ongoing investigation by Robert Mueller into the role played by Russia in the 2016 election. WGBH's Morning Edition anchor Joe Mathieu discussed the implications and more with WGBH News legal analyst and Northeastern law professor Daniel Medwed. This transcript has been edited for clarity.

Joe Mathieu: So now, Trump replaced Sessions with his former chief of staff, Matthew Whitaker, who will serve as the acting attorney general. Do you anticipate significant changes in federal policy as a result here?

Daniel Medwed: Well, not necessarily. In his nearly two years at the helm of main Justice, Sessions cut back on a number of Obama-era policies including those related to drugs and immigration. And, he was much more lenient on law enforcement. In his last act before departing, he vastly curtailed the use of consent decrees, which are a common federal tool designed to monitor local dysfunctional police departments. I see no reason why Whitaker would deviate from this Sessions' agenda except perhaps when it comes to recusal. Now this has been in the news — should he recuse himself from the Mueller probe? To his credit, Sessions did recuse himself. It's a lot less clear whether Whitaker will follow suit.

Mathieu: You mentioned the secret word here, and that's recusal. The Justice Department has just announced just last night, on a Monday holiday, that Whitaker will consult with ethics officials at the DOJ about his oversight of the Mueller probe. So should he recuse himself?

Medwed: I think he should, but it's a separate question, of course, whether he will. Now recusals are largely discretionary and they're most clearly warranted when there is a direct conflict of interest, as in the case of Jeff Sessions. So the Mueller probe is investigating ties between the 2016 Trump campaign and Russia. Sessions was a vital cog in the 2016 Trump campaign machine so he had he not recused himself then, in effect, he would have been overseeing an investigation that could be looking into his own missteps. Now Whitaker's conflicts of interests are also sizable but admittedly more indirect. For one thing, he's gone on the record criticizing the Mueller probe as having gone too far. For another thing, he has close personal and professional ties to an Iowa politician named Sam Clovis, who is apparently a witness in the Mueller probe. So taken together, this at a minimum, creates the appearance of impropriety. Whitaker should step down. I suspect and hope that the DOJ is telling him to do so. But that doesn't mean he will. He's a Trump loyalist, I suspect that's why he was tapped for this role. He might very well dig in his heels and refuse to step down.

Mathieu: It's been suggested, while the president has denied this, that this may have been arranged in advance, right? We're talking with WGBH News legal analyst Daniel Medwed about the consequences of the firing of Jeff Sessions as attorney general. You mentioned that Whitaker may well recuse himself, we have yet to learn, but is there an argument that his appointment itself is unconstitutional? I've heard this come up because he has not been confirmed by Congress.

Medwed: A fascinating issue. There are a whole host of constitutional and legal questions swirling around his appointment and they basically boil down to this: The Constitution has something called the appointments clause which provides that principal officers can only take their seats upon the advice and consent of the Senate. Now an attorney general, like a Cabinet secretary, is undoubtedly a principal officer and Whitaker has not gone through the requisite confirmation process. So the real question then becomes: may Trump appoint someone in an acting capacity in this fashion, without running afoul of the appointments clause?

Mathieu: And that's all we have, right? He's the acting attorney general.

Medwed: That's right.

Mathieu: And the way in which this went, we're not sure exactly if Jeff Sessions was fired or resigned or maybe a little bit of both.

Medwed: Exactly. So the outcome of this legal dispute — the constitutional dispute — I think hinges to some extent on whether Sessions, as you said, resigned or was fired. His letter was quite ambiguous. He resigned but strongly intimated that he did so under pressure.

Mathieu: At the White House's request.

Medwed: At the White House's request. So on the one hand, if it turns out that Sessions resigned, then Trump is maybe within his rights, under a law called the Federal Vacancy Reform Act, to appoint a temporary replacement who's not been Senate confirmed for up to 210 days. But on the other hand, if Sessions happened to have been fired, then potentially this exceeds the bounds of that act — the FVRA. And none other than Justice Clarence Thomas, in an opinion last year, has gone on the record criticizing the executive branch for "doing end runs around the appointments clause like this" potentially. So we'll have to stay tuned and see how this all plays out.

Mathieu: It sounds like we’re going to be talking about this again. WGBH News legal analyst and Northeastern law professor Daniel Medwed. This is Morning Edition.