Trump prepares to remake his Cabinet

US President Donald Trump speaks to the press during a Cabinet meeting at the White House on December 6, 2017 in Washington, D.C.

(CNN)As Washington awaits a potential reshaping of the political order on Capitol Hill, multiple sources inside and outside the Trump administration tell CNN that an all but certain shakeup is quietly underway at the White House, as President Donald Trump is poised to reshuffle his Cabinet for the second half of his first term.

Trump acknowledged as much on Monday. "Administrations makes changes, usually, after midterms. And probably we'll be right in that category as well," he told reporters at Joint Base Andrews on his way to a rally in Ohio. "I think it's very customary."
The President has made little secret of his furor at several members of his Cabinet, with Attorney General Jeff Sessions at the top of the list. His relationship with Defense Secretary James Mattis has steadily faded, with the two talking far less than they did during the first year of Trump's term. And his anger toward Homeland Security Secretary Kirstjen Nielsen has bubbled into public view on several occasions, with the President blaming her for failing to solve the intractable challenge of illegal immigration.
    As the halftime mark of his first term approaches, the President is increasingly talking to allies and advisers about the potential for sweeping change in his Cabinet. While as many as half a dozen may end up leaving, three names in particular-- Sessions, Mattis, Nielsen -- are at the top of many internal conversations about the Cabinet secretaries most likely to leave, along with White House chief of staff John Kelly. Another is already on her way out. Last month, US Ambassador to the United Nations Nikki Haley announced her intent to leave at the end of the year.
    Even so, two White House officials and one outside confidant to the President tell CNN that the changes may be less urgent than many people assume. The timetable may also be dictated by the outcome of the midterm elections. "No one leaves quickly around here," one official said, speaking on condition of anonymity to discuss deliberations inside the West Wing. "Even people the President wishes were gone."

    Jeff Sessions

    That especially applies to Sessions, whom Trump has spent months openly ridiculing because of his recusal from the Russia investigation, issuing blistering performance reviews in media interviews and tweets, and even going so far as proclaiming, "I don't have an attorney general," during an interview with The Hill in September.
    For his part, Sessions has generally declined to spar with the President, choosing instead to keep his head down and go about his job while continuing to support Trump's policies (both privately and publicly). He's also managed to adopt a stoic sense of humor about his situation. To mark the anniversary of his first year in office, staff aides gave Sessions a bulletproof vest as a gag gift. Many Republican lawmakers have said Sessions should stay put. And Trump's attacks haven't gone over well with voters in Alabama, where Sessions remains popular.
    Still, Sessions constantly finds himself in the cross-hairs of Trump, most recently during an Axios interview in which the President said Sessions did not give him prior notice before the Justice Department urged a court to throw out provisions in Obamacare that protect pre-existing conditions. Not only is that at odds with Trump's recent rhetoric on the campaign trail promising to protect patients with pre-existing conditions, but Sessions also has said that Trump signed off on the move.
    It's all led to widespread speculation that Sessions could be the first to go. His departure would trigger a complex set of options for the President. If Trump does not immediately name a temporary replacement, then Deputy Attorney General Rod Rosenstein, the current No. 2 at the Justice Department, would act in Sessions' place. Given that Rosenstein has already stepped into Sessions' shoes to oversee special counsel Robert Mueller's investigation, allowing Rosenstein to serve as the acting attorney general until Trump's permanent choice is confirmed could provide the least disruptive path forward.
    Senate leadership has privately signaled that another attorney general nominee would not get confirmed during the lame duck session after the midterms, according to a source familiar with the matter, further curtailing Trump's ability to quickly swap out Sessions.
    If Trump opts to tap someone else as acting attorney general in lieu of Rosenstein before Mueller's probe is finished, the political blowback could be strong, especially if the move is perceived as a way to undermine the special counsel's work.
    In the wake of reports that Rosenstein may resign or be fired in late September, Justice officials began planning for Solicitor General Noel Francisco to step in as acting attorney general to oversee Mueller. They also made plans to name Matthew Whitaker, Sessions' current chief of staff, as the acting deputy attorney general. And while Whitaker has spoken with Trump directly about his future at the Justice Department, reportedly even contemplating taking his boss's job, the White House has been informed that he too would likely have to recuse from the Russia investigation in light of some of his past writings and TV appearances. Plans of his ascension appear to have stalled. Moreover, there seems to be little appetite for Francisco to assume the acting attorney general slot if Rosenstein remains in place for now.
    One Trump ally told CNN that the White House is now looking for someone who is "not real partisan" when asked about candidates to permanently replace Sessions. The source acknowledged the swirl of rumors that it might be a sitting lawmaker -- Republican Sen. Lindsey Graham of South Carolina has been repeatedly asked about the job. He's also repeatedly said he's not interested.
    Other names that have been floated as possible replacements for Sessions include Rep. John Ratcliffe of Texas, a former federal prosecutor, as well John Michael Luttig, a former US Court of Appeals judge and Justice Department official, and current general counsel at Boeing. One former White House official said Luttig is a strong possibility. A second source close to Luttig says that he was considered for the role of FBI director after James Comey was fired.
    A Hill source also mentioned that federal Judge Edith Jones, who sits on the 5th US Circuit Court of Appeals, might also be in play.
    Janice Rogers Brown has also emerged as a possible candidate. Brown, a former California Supreme Court associate justice and former US circuit judge, retired from the bench in August 2017 and moved back to California. A source close to her indicated that she would not be interested in the AG job and doesn't want to return to Washington.

    John Kelly and Jim Mattis

    One of the biggest dynamics to watch -- and one of the biggest mysteries in Washington -- is between Kelly and Mattis, both retired Marine Corps generals, and whether they have an unspoken agreement to stay as long as possible. Two questions remain unanswered for several people close to the White House: Will they stay on until fired? Or will they resign and let the President shape his team for the next phase of his first term?
    In July, Kelly made a showy declaration that Trump had asked him to remain as chief of staff until 2020, and that he'd agreed. But even that pronouncement did little to quiet speculation -- both inside and outside the White House -- that he could depart at any time.
    Mattis' future was brought into question most recently after Trump, in a September interview with "60 Minutes," labeled Mattis as "sort of a Democrat" while saying the retired general "may leave" and that "at some point, everybody lea