This article is more than 1 year old

This article is more than 1 year old

The deputy attorney general, Rod Rosenstein, privately complained that he was ordered by president Donald Trump to write the notorious memo justifying the firing of the FBI director James Comey, according to Comey’s former deputy.

Andrew McCabe writes in a new book that Rosenstein, who has publicly defended the memo, lamented that the president had directed him to rationalise Comey’s dismissal, which is now the subject of inquiries into whether Trump obstructed justice.

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Rosenstein made his remarks in a private meeting at the justice department on 12 May 2017, according to McCabe’s memoir, which also accuses Trump of operating like a criminal mob boss and of unleashing a “strain of insanity” in American public life.

McCabe recalls Rosenstein being “glassy-eyed”, visibly upset and sounding emotional after coming to believe the White House was using him as a scapegoat for Comey’s dismissal.

“He said it wasn’t his idea. The president had ordered him to write the memo justifying the firing,” McCabe writes. Rosenstein said he was having trouble sleeping, McCabe writes. “There’s no one here that I can trust,” he is quoted as saying.

McCabe’s book, The Threat: How the FBI Protects America in the Age of Terror and Trump, is due on sale later this month. A copy was obtained by the Guardian prior to its release.

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The account supports reports last year that Rosenstein was left “shaken” by his role in Comey’s firing. It provides the strongest indication so far that Rosenstein’s private view on the memo clashed with his testimony to Congress saying: “I wrote it. I believe it. I stand by it.”

His memo was cited by Trump as a reason to fire Comey over his handling of the FBI inquiry into Hillary Clinton’s email use as secretary of state. Trump later said that he in fact fired Comey for pursuing the investigation into his presidential campaign’s links with Russia.

At the time, the White House flatly denied that Trump had directed Rosenstein to write a justification for firing Comey. “It was all him,” Sean Spicer, the then press secretary, said of Rosenstein.

Five days after his emotional remarks, Rosenstein appointed Robert Mueller, the special counsel, to take over the inquiry into whether Trump’s team coordinated with Russia’s interference in the 2016 election. US authorities concluded Russia aimed to help Trump.

Mueller is also known to be investigating whether Trump sought to obstruct justice by firing Comey and taking other steps to impede the investigation.

McCabe, a 22-year FBI veteran who was fired after internal investigators said he had been dishonest, is scathing about a president he views as posing a threat to the country. He accuses Trump of undermining the FBI out of fear and diminishing the rule of law.

In his sharpest criticism, McCabe writes that after firing Comey, Trump and the White House counsel, Don McGahn, acted like mobsters by in effect offering McCabe protection in return for loyalty.

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“The president and his men were trying to work me the way a criminal brigade would operate,” McCabe writes, recalling an Oval Office meeting soon after his elevation to acting FBI director.

He confirms reports that Trump asked him how he voted in 2016. Having been a lifelong registered Republican, McCabe writes, he did not cast a vote for president that year. McCabe was later publicly attacked by Trump, who abused him and his wife in tweets.

McCabe portrays Trump and his senior aides as frequently distracted by TV news and suspicions of leakers in the White House. He is also sharply critical of Jeff Sessions, Trump’s first attorney general, saying he had trouble focusing, frequently flew into red-faced rages and confused classified intelligence with things he had read in the media.

He accuses Trump of using the tactics and rhetoric of totalitarian dictators in persuading loyal “shock troops” that anyone who disagrees with them is a traitor.

Trump’s “heedless bullying” and refusal to tolerate any view other than his own is “nurturing a strain of insanity in public dialogue” that is then further amplified by online media, McCabe writes.

The book does not reveal new findings from the Trump-Russia investigation but gives a tantalizing detail within what McCabe says is a “hypothetical” that explains FBI protocol.

If the bureau learns that someone from a US political campaign and a high-ranking foreign official discussed “possibly colluding”, he writes, then the FBI would be obliged to investigate.