If thewasn't enough to elicit concern from Trump critics in Washington, replacing him with Acting Attorney General Matt Whitaker certainly has.
While President Trump searches for a— something Trump ally — Whitaker oversees special counsel Robert Mueller's investigation into Russian election meddling and any ties to Trump associates.
Democrats are already urging Whitaker to recuse himself from the investigation, givenon television and in print criticizing the scope and authority of Mueller's investigation. But Mr. Trump never forgave Sessions for recusing himself from the investigation, and publicly and repeatedly berated his attorney general for doing so. Whitaker has given no indication that he intends to recuse himself after assuming the oversight baton from Deputy Attorney General Rod Rosenstein.
"Deputy Attorney General Rod Rosenstein's office has been involved in the daily oversight of Mueller's investigation from the outset, and it would be difficult both legally and as a political matter to completely cut his office out of that role going forward," said Robert Mintz, a former federal prosecutor who is now a partner at the McCarter & English law firm. "But there are no defined rules within the DOJ that directly address these issues, and how this shift in leadership within the Department will impact the Mueller probe is difficult to predict."
So, what authority may Whitaker flex in the Mueller probe, and how?
Could he fire Mueller?
In short, "Yes. But he needs to find good cause to do so," said Rebecca Lonergan, a former assistant U.S. Attorney who now teaches at the University of Southern California's Gould School of Law.
Federal regulations governing a special counsel say that counsel may be "disciplined or removed from office only by the personal action of the attorney general."
"The attorney general may remove a special counsel for misconduct, dereliction of duty, incapacity, conflict of interest, or for other good cause, including violation of departmental policies," the code continues. "The attorney general shall inform the special counsel in writing of the specific reason for his or her removal."
Mr. Trump has said he doesn't want to fire Mueller, for political reasons.
"I could fire everybody right now," Mr. Trump said in a post-midterms presser last week,. "But I don't want to stop it because politically, I don't like stopping it."
Lonergan doesn't think Whitaker will fire Mueller — but he could thwart the investigation in other ways.
Could Whitaker cut Mueller's budget?
Whitaker certainly seems to think he could cut slash Mueller's budget. In July 2017, he told CNN's Don Lemon he could envision a scenario in which the "attorney general doesn't fire Bob Mueller but he just reduces his budget to so low that his investigations grind to almost a halt."
Lonergan said slashing Mueller's budget is a more realistic possibility than firing him. Mueller's budget and the resources available to him — like additional personnel needed from DOJ — are up to Whitaker now.
"So if you take away the resources you really, really can make the investigation impossible to complete," Lonergan said.
Whether Whitaker would considerably attempt to scale back Mueller's probe remains to be seen, said Michael Mukasey, former attorney general under George W. Bush.
"If he's the attorney general then he can control the scope of the investigation and can, on a year to year basis, control the budget that's in the regulation," Mukasey, who has suggested the end of Mueller's investigation is overdue, told CBS News in a phone interview. "Whether he would do that with all the yelling and screaming that would go on is a whole different thing."
Whitaker might not be able to hack away at Mueller's budget until next year, however, as the special counsel is funded through the end of the current fiscal year ending after September 2019.
Could he control the scope of Mueller's investigation?
Whitaker has certainly been critical of the scope of Mueller's investigation, writing an entire op-ed for CNN on that topic last year.
In an August 2017 opinion piece with the title, "Mueller's investigation is going too far," Whitaker made the case that probing the president's finances would cross an invisible line.
"It does not take a lawyer or even a former federal prosecutor like myself to conclude that investigating Donald Trump's finances or his family's finances falls completely outside of the realm of his 2016 campaign and allegations that the campaign coordinated with the Russian government or anyone else. That goes beyond the scope of the appointment of the special counsel," Whitaker wrote at the time.
That op-ed, written before Whitaker joined the Justice Department as Sessions' chief of staff, is one of the main reasons Democrats are citing to justify why they believe he should recuse himself, or even resign.
Lonergan said that Whitaker might find it difficult to scale back the scope of Mueller's investigation. But if Mueller's team wants to review something it believes falls under its broad original jurisdiction and Whitaker disagrees that such a subject of investigation falls within that scope, Whitaker could likely keep Mueller from examining that area.
He could set parameters around any entirely new areas the special counsel wants to probe that don't fall within the original jurisdiction, Lonergan said.
"The AG has a lot of power over where the investigation goes," Lonergan said.
In a nutshell, Whitaker's latitude is broad.
"As the acting attorney general, Matt Whitaker now has the full authority within the Department of Justice to oversee the Mueller investigation," Mintz said. "That means that technically he has the discretion to manage the investigation, control Mueller's budget and direct the scope of the special counsel's team of prosecutors, or fire Mueller altogether."
What's the deal with recusal?
Democrats are urging Whitaker to recuse himself from the Mueller probe due to his past critical comments. But Whitaker hasn't made any indication he will do so, and it seems less likely he would do so after Mr. Trump repeatedly blasted Sessions for his recusal, even claiming that he had no attorney general.
Sessions' official recusal statement in March 2017 said he separated himself from "any existing or future investigations of any matters related in any way to the campaigns for president of the United States" last year after conferring with "relevant senior career department officials."
This time around, Whitaker, too, is consulting top DOJ officials. The Justice Department, after days of silence, confirmed to CBS News correspondent Paula Reid that Whitaker will consult with senior ethics officials.
"Acting Attorney General Matt Whitaker is fully committed to following all appropriate processes and procedures at the Department of Justice, including consulting with senior ethics officials on his oversight responsibilities and matters that may warrant recusal," DOJ spokesperson Kerri Kupec said.
Mukasey doesn't believe statements made prior to Whitaker's time at DOJ fall under a category for recusal.
"If you make statements and write articles before you take office, that doesn't require you to recuse yourself," Mukasey said.
But Whitaker doesn't have to follow through with any recommendation made.
"As a practical matter, any recusal decision will rest with Whitaker, and it seems highly unlikely that he will recuse himself from the Mueller investigation, given the history of recusal with former Attorney General Sessions," Mintz said.
What about Whitaker's appointment in the first place?
Still, Whitaker's appointment itself is facing legal questions. Maryland's attorney general has already filed a lawsuit claiming Whitaker's appointment is "illegal and unconstitutional."
"The Constitution and Congress have established vitally important processes for filling high-level vacancies in the federal government," Attorney General Brian Frosh said in a statement. "Few positions are more critical than that of U.S. Attorney General, an office that wields enormous enforcement power and authority over the lives of all Americans. President Trump's brazen attempt to flout the law and Constitution in bypassing Deputy U.S. Attorney General Rosenstein in favor of a partisan and unqualified staffer cannot stand."
Lonergan pointed out that Article II of the Constitution says the president may nominate principal officers "with the advice and consent of the Senate." The Federal Vacancies Reform Act does allow for a 210-day window for a non-Senate confirmed selection to serve as an "acting officer," but Lonergan said the Constitution may "trump" that vacancy law. Further, federal law says the deputy attorney general shall fill the vacancy left by an attorney general.
"So it's not entirely clear, but it's arguably unconstitutional to put him into a high-level Cabinet principal officer" position, Lonergan said.
CBS News correspondent Paula Reid contributed to this report.