But his refusal to answer a question about who directed him to write the infamous memo suggests he might also be a witness to a crime being investigated by the special counsel. Had he been appointed again by Mr. Trump, Congress would likely have to weigh in again.
But it is a line of thinking that is making its way to the president's ears.
Rosenstein, who has the sole ability to fire Mueller given that Attorney General Jeff Sessions has recused himself from matters relating to the investigation, told the panel he had seen no evidence of good cause for letting Mueller go and that he would not follow any theoretical order to fire him absent such evidence.
Just weeks ago, Gingrich had heaped praise on Mueller, hailing him as a "superb choice" for special counsel whose reputation was "impeccable for honesty and integrity". "If there were good cause, I would consider it", Rosentsein said, adding, "If there were not good cause, it wouldn't matter to me what anybody says". Justice Department regulations specify that a special counsel can only be removed for "misconduct, dereliction of duty, incapacity, conflict of interest, or for other good cause", and that the "specific reason" must be spelled out in writing.
Rosenstein's letter critical of Comey's handling of the Hillary Clinton email server investigation served as the Trump White House's first reasoning for firing Comey - though Trump later undercut that explanation by saying he fired Comey in hopes of ending the Russian Federation probe. White House sources have told ABC News that the president is not seeking to fire Mueller, but a close confidante of Trump's said Mueller's ousting is under c.More news: Tiger Woods DUI Video Released
More news: Fellow Republicans press Donald Trump about Comey tapes
More news: Trump dismisses 'leaker' James Comey's version: 'I didn't say that'
The official, who would not detail what the two discussed during the interview, said it took place on May 16.
The White House forcefully disputed Ruddy's claims, saying he speaks for himself, not the president.
In a February meeting, Comey said, Trump told Sessions and other administration officials to leave the room before asking him to drop a probe into former National Security Adviser Michael Flynn's contacts with Russian Federation.
In yet another blow to the president's agenda, the 9th Circuit Court of Appeals ruled against Trump's executive order limiting travel to the United States from several Muslim-majority countries.
"I can't imagine that that issue is going to arise", he added. He said Trump is "actually pretty confident" that "ultimately, he's still going to be president and this stuff is all going to go away". "It is certainly theoretically possible that the attorney general could fire him, but that's the only person who has authority to fire him. Ruddy never spoke to the president regarding this issue", Spicer said.
Jack Goldsmith, a Harvard Law professor who headed the Justice Department's Office of Legal Counsel during the George W. Bush administration, offered a careful assessment of the consequences of a Mueller firing early Tuesday on the Lawfare blog.