WASHINGTON — “Are you O.K.?” Andrew G. McCabe, the acting F.B.I. director, asked Rod J. Rosenstein, the deputy attorney general.
“No,” Mr. Rosenstein replied.
“Are you getting any sleep?” Mr. McCabe asked.
“No,” he said.
It was Friday morning, May 12, 2017, three days after President Trump had summarily fired James B. Comey as the F.B.I. director.
The conversation is described in a new book that portrays Mr. Rosenstein as anguished and isolated as he struggled with the realization that Mr. Trump might have ousted Mr. Comey to obstruct the F.B.I.’s investigation of Russian interference in the 2016 election — and that he would probably have to appoint a special counsel to take over the inquiry, even if it cost him his job.
The book, “Deep State: Trump, the F.B.I. and the Rule of Law” by James B. Stewart, provides new details about the history-making interactions between top Justice Department and F.B.I. officials immediately after the president ousted Mr. Comey. It recounts how Mr. Rosenstein was so troubled by Mr. Trump’s behavior that he twice proposed that he secretly wear a wire and record the president in the White House, the second time in the presence of an F.B.I. official who took notes.
Drawing heavily on reporting by The New York Times, Mr. Stewart, a Times reporter, also fleshes out how Mr. Rosenstein raised with Mr. McCabe the possibility of invoking the 25th Amendment, which allows a vice president and a majority of cabinet members to remove an unfit president from office. In a new detail, he wrote that Mr. Rosenstein told Mr. McCabe during a May 16, 2017, meeting that Attorney General Jeff Sessions and John F. Kelly, the homeland security secretary, would most likely support such a move.
“At times he got up and walked around the table,” Mr. Stewart wrote of Mr. Rosenstein during the meeting in the deputy attorney general’s office. “At one point, he was so upset he went into an adjoining bathroom to compose himself.”
That evening, Mr. Rosenstein revealed that Mr. Trump wanted Mr. Kelly to run both the F.B.I. and the Department of Homeland Security as part of a “strategy for disruption,” according to the book. “You’ve got to be kidding,” Mr. McCabe told him.
For his part, Mr. Kelly was deeply disturbed by Mr. Comey’s ouster. He called Mr. Comey as soon as he learned of it, saying that “he felt sickened by Trump’s decision to fire him and wanted to quit in protest,” the book said. “He didn’t want to work for someone so dishonorable.”
Those reservations were apparently short-lived: Mr. Kelly went on to serve as Mr. Trump’s chief of staff for 17 months.
The book does not resolve the mystery of how Mr. Rosenstein managed to hang onto his position after The Times, more than a year later, reported the gist of his conversations about the 25th Amendment and secretly recording the president.
Mr. Rosenstein at the time publicly dismissed The Times’s September 2018 article as “factually incorrect.” He added in a statement, “Based on my personal dealings with the president, there is no basis to invoke the 25th Amendment.”
Despite widespread speculation that the president would fire him, Mr. Rosenstein remained in his post until this May, overseeing the investigation by special counsel, Robert S. Mueller III, through its conclusion.
The book also offers new details about the F.B.I.’s decision to open a counterintelligence investigation into Mr. Trump one week after he fired Mr. Comey. According to Mr. Stewart, the firing itself convinced Mr. McCabe and four other top F.B.I. officials that they had sufficient reason to open the inquiry into whether Mr. Trump had acted at Russia’s behest. The decision was unanimous, according to the book.
On May 17, the day after he met with Mr. Rosenstein, Mr. McCabe briefed the so-called Gang of Eight, a bipartisan group of senior congressional leaders privy to major intelligence issues, about the decision. According to Mr. Stewart, only Speaker Paul D. Ryan, Republican of Wisconsin, asked a question. He wanted to know if the investigation was also a criminal inquiry; Mr. McCabe said criminal charges could result.
Mr. Rosenstein, who also briefed the congressional leaders, appointed Mr. Mueller as the special counsel the same day.
Before the president fired Mr. Comey, Mr. Rosenstein had written a memo suggesting that Mr. Comey should be dismissed. But it quickly became clear to him that his arguments for terminating Mr. Comey were entirely different from the president’s.
Mr. Rosenstein had argued that Mr. Comey made critical errors in handling the F.B.I.’s investigation into Hillary Clinton’s use of a private email server while she was the secretary of state.
But when the White House tried to pressure Mr. Rosenstein to state publicly that firing Mr. Comey had been his idea, not the president’s — thus cloaking the president’s real motivation — Mr. Rosenstein refused, with Mr. Sessions’s backing. He said he would not be part of a “false story,” Mr. Stewart wrote. In a broadcast interview two days after he fired Mr. Comey, Mr. Trump admitted that he acted because of “this Russia thing,” not Mr. Rosenstein’s memo.
According to the book, the sense that Mr. Trump had used him deeply unsettled Mr. Rosenstein, who had been in his post less than two weeks. Mr. Stewart described the May 12 meeting with Mr. McCabe in detail, saying that Mr. Rosenstein struggled to keep his emotions in check.
“His voice was wavering, his eyes teared up. He said he couldn’t believe what was happening,” according to Mr. Stewart’s account.
“There’s no one here I can talk to about this. There’s no one I can trust,” Mr. Rosenstein confided to Mr. McCabe, whom he knew only slightly.
He added, “The one person I wish I could talk to is Jim Comey.”