(CNN) US Solicitor General Noel Francisco is expected to resign from his role as the government's top lawyer before the Supreme Court in the coming days, according to two sources familiar with the move.
Francisco, 50, has led the solicitor general's office since September 2017 and been a forceful advocate for President Donald Trump. The White House is not expected to immediately name a permanent successor. Instead, the principal deputy solicitor general, Jeff Wall, will most likely be tapped as the acting solicitor general.
Patrick Philbin, the deputy White House counsel, had previously been rumored as a frontrunner for the position, but apparently the succession plan is still in flux, two sources said.
The White House and Department of Justice did not immediately respond to requests for comment.
As the face of the Trump administration at the Supreme Court lectern, Francisco argued for the travel ban that targeted majority-Muslim countries, for a citizenship question on the US Census, and most recently for an end to the Obama-era program that shields young immigrants who were brought to the US without proper documentation.
Francisco also has taken the lead for the Department of Justice in its briefs supporting Trump's efforts to block subpoenas from the US House of Representatives and a New York grand jury for personal financial documents, including tax returns.
The administration won the travel ban case in 2018 and last year lost on the battle over a citizenship query on the 2020 census. The Supreme Court is scheduled to rule in upcoming weeks on the Trump administration's plan to phase out the Deferred Action for Childhood Arrivals (DACA) program and subpoenas against Trump's longtime accountants and banks.
Francisco has also been aggressive -- and largely successful -- in seeking Supreme Court intervention when lower court judges have blocked Trump policies, for example on anti-immigration efforts, at early stages of litigation, for example.
While an acting solicitor general is expected to replace Francisco in the near term, it was not immediately clear who may be tapped to replace him on a permanent basis. Deputy White House Counsel Philbin had previously been thought to be a choice, but a source familiar with the dynamic told CNN that Philbin's boss, White House counsel Pat Cipollone, does not want him to leave his office yet. It's unclear how the matter will ultimately be resolved, and a person close to Cipollone disputed he would block Philbin's exit if he was up for a promotion.
The White House did not immediately respond to a request for comment. The Justice Department did not immediately respond to a request for comment.
No specific reason for Francisco's departure was given but solicitors general and other top Justice Department officials have sometimes stepped down near the end of an administration's term.
Before joining the Trump administration, Francisco had served in the George W. Bush administration and more recently, worked in private practice at the Washington, DC, office of Jones Day. He represented former Virginia Republican Gov. Robert McDonnell in 2016 when the Supreme Court unanimously overturned McDonnell's conviction on corruption charges.
Francisco's Senate confirmation hearing was in May 2017, the day after Trump fired James Comey as FBI director.
Philbin recently played a major role in representing Trump during his Senate impeachment trial earlier this year and is the White House counsel's top lieutenant.
Philbin was reportedly up for a job in the solicitor general's office before -- in the 2000s, when George W. Bush was in office -- only to be denied a promotion because of a role he played in reviewing the legality of the federal government's domestic spying program, according to what Comey later told investigators.
The program came under intense scrutiny in 2004, when then-Attorney General John Ashcroft was hospitalized with gallbladder complications. In his absence, Comey, then deputy attorney general, had been tasked with carrying out his responsibilities, and later refused to reauthorize the program during a dramatic standoff in Ashcroft's hospital room. Philbin -- then the associate deputy attorney general -- was present when Comey told then-Vice President Dick Cheney that the Justice Department would not reauthorize the spying program
Years later, Comey testified in written documents that he believed Philbin was blocked from the job by Cheney as retaliation.
This story has been updated with additional developments.