One of the rare anecdotal gems in A Warning, the book by Anonymous, a senior White House official, is how Donald Trump reacts to anyone trying to keep a record of meetings. “What the f*** are you doing?” the US president asks. “Are you f***ing taking notes?” Staff take this as a classic signal that he is about to ask his lawyers to do something unethical, says Anonymous. Which is to say it is a regular event.

Some of Trump’s paranoia can be attributed to Fusion GPS, the Washington investigative firm set up by former journalists, which commissioned Christopher Steele to write his dossier. The former British intelligence agent came up with the most infamous piece of opposition research in US history.

People still speculate about the veracity of allegations of bizarre sexual exploits — the so-called Moscow “pee tapes”. Glenn Simpson and Peter Fritsch, the Fusion GPS founding partners, who have written a compelling narrative of the still unfinished saga, estimate that the “Steele dossier” got it about 70 per cent right. Others, including Bob Woodward, the Watergate investigative journalist, called it a “garbage document”. Woodward, however, was starting out on an insiders’ account of the Trump administration, which required the subjects of his book to trust him. His verdict earned a presidential thank you on Twitter.

Neither of these books are likely to elicit any gratitude from Trump. The first, Crimes In Progress, is the most convincing case you are likely to read that the US president is an asset of the Russian government. Outlandish though that may sound, it will seem less so when you turn the final page. The second, by an author still working in the White House, and whose identity Trump would dearly love to expose, is a moral indictment of his presidency. Each sheds important light on the least likely president in American history.

One of the oddities of this week’s articles of impeachment against Trump is that they excluded the findings of Robert Mueller, the special counsel, on the president’s alleged Russia collusion during the 2016 election. Though Mr Trump’s quid pro quo on Ukraine was aimed at procuring foreign meddling in a US election, it was geared towards next year, not what happened in 2016. Mueller’s two-year investigation is often described as exhaustive. In fact, it was narrowly focused on suspected conspiracy between the Trump campaign and the Kremlin.

As Simpson and Fritsch point out, Mueller chose not to follow the money. He did not look into Trump’s taxes, his ties with Russian money, allegations of money laundering or his relationship with Deutsche Bank. Nor did Mueller’s team contact Fusion GPS or Steele. Had he done so, his 448-page report would have been longer but probably easier for the public to grasp. “The central message of Steele’s dossier was strikingly right,” say the authors.

Fusion GPS was commissioned to investigate Trump in September 2015, more than a year before the election, by the Washington Free Beacon, a conservative news website owned by hedge fund billionaire Paul Singer. Simpson and Fritsch thought it would take a month. Over the coming year they built up an “alternative Trump presidential library”. Mueller documented more than 140 contacts between the Trump campaign and the Russian government, mostly surreptitious — though he was unable to prove conspiracy.

Fusion GPS found that Trump had done business with 25 individuals or companies with “documented mob ties” over the years. The length of Trump’s litigation record dwarfed anything they had ever seen. Trump, they concluded, was the “textbook definition of a charlatan”: a self-declared business genius with a history of bankruptcies; a supposed billionaire whose true assets were a fraction of that; a self-made entrepreneur who inherited $400m; an immigrant-basher who employed hundreds of illegal immigrants; an America First proponent who outsourced his clothing line to Mexico.

Most importantly, they discovered that Trump owed the revival of his commercial fortunes to the “conduit of cash from the former Soviet Union into his various stumbling enterprises”. Much of it is thought to have come from Russian banks close to the Kremlin. Other than Deutsche Bank, no other international lenders would touch him. Such material was grist to the Washington Free Beacon’s mill until it became obvious that Trump would win the Republican nomination for president. It dropped the contract in May 2016. Fusion GPS quickly found a new client — a law firm representing Hillary Clinton’s campaign.

The Republican case against Fusion GPS is that Steele is a fraud, who independently alerted the US department of justice to the contents of his dossier, which, in turn, triggered the phoney FBI investigation of Trump that led to the Mueller inquiry. In fact, Steele did not know the identity of his ultimate client. Plus, the FBI was separately alerted to the alleged collusion by Alexander Downer, Australia’s then ambassador to the UK, who was made aware of it by an unwitting junior Trump campaign adv­iser. Moreover, the Steele dossier only became known to the public in January 2017 after it was published on the BuzzFeed news site two months after Trump was elected. It was leaked by an adviser to John McCain, the Republican senator.

[Trump’s staff are] like bank-robbery hostages lying on the floor at gunpoint, unable to sound the alarm but aware that everyone else was stricken with the same fear

Among those pressing for its dissemination was Lindsey Graham, the Republican senator from South Carolina, who is now a fierce Trump loyalist. Graham, like the Washington Free Beacon, had a Damascene conversion. Mueller eventually indicted 34 people. Several of these, including Trump’s campaign manager, Paul Manafort, his former personal lawyer, Michael Cohen, and his longtime consiglieri, Roger Stone, and former lobbyist, are now in prison. The authors believe the case that Trump conspired with Russia is robust: “There is no other plausible explanation for Trump’s ongoing subservience to Putin’s agenda, and the continuing campaign of obstruction and co-ordinated lies,” they opine. Mueller missed his target, in other words. Their book does not.

There has been some speculation about the identity of Anonymous, who describes him or herself as a senior White House official. But probably not as much chatter as the publisher would have liked. So much is known about Trump that a very high bar must be cleared to shock the public. A Warning, nevertheless, contains some revealing insights. Trump is so averse to seeing anything in writing that staff have whittled briefings down to one slide with lots of visual razzmatazz and only one point — preferably attributed to Trump himself. That point must then be repeated again and again. Anything more detailed would be like “speaking Aramaic to Trump through a pillow”.

One-third of the ideas he proposes are “flat-out stupid”. One-third are impossible to implement. And one-third seem “flat-out illegal”. One of the low points was when staff had to make frantic preparations for Trump’s summit with Kim Jong Un, North Korea’s dictator, which most saw as a dangerously misguided love-in. It was like planning for “Trump’s quinceañera [the coming-of-age party for Hispanic girls]”, writes Anonymous.

His dazed staff are “like bank-robbery hostages lying on the floor at gunpoint, unable to sound the alarm but aware that everyone else was stricken with the same fear”. So paranoid is Trump about the deep state that he often holds “politicals only” meetings in the White House situation room on subjects unrelated to national security. Of all those who work for Trump, Mike Pence, his vice-president, exhibits the clearest traits of Stockholm syndrome — loving your captor.

The clearest tell-tale sign of a Trump apologist, says Anonymous, is someone who is frequently seen “smiling and nodding at the wrong time”. Most of the staff, however, are just doing what it takes to make it through the day. At a Pence-organised event last year to announce a new US mission to the Moon, Trump departed from the script to say American space ships would in fact be landing on Mars. “We’re already on it,” emailed one Pence staffer.

Those seeking impeachable material should probably avoid A Warning. Those who prefer a moral case will come away fortified, if not entirely surprised. The book is a scream of conservative outrage against a president who is making a mockery of conservative principles. At one point, the author issues a pertinent warning from history. At a tense phase in the Peloponnesian war, the citizens of Athens held a debate about what to do with the city of Mytilene, a small city-state that had defected to Sparta.

Half the assembled Athenians wanted to kill every Mytilenian man, woman and child in reprisal. They were swayed by the bombastic Cleon, a prominent Athenian who had leveraged his father’s wealth to enter politics. The other half, led by the tempered Diodotus, argued for restraint. Diodotus narrowly prevailed. A few years later the Athenian mob voted to slaughter every inhabitant of the island of Melos for the same transgression. A generation after that, Socrates, the “ ‘wisest man’ to have ever lived”, was put to death. Ancient Greek democracy never recovered. Cleon’s demagogic seed had come to fruition.

If Trump wins next year, a similar fate could await the US republic, warns Anonymous. “By then the guardrails will be gone,” Anonymous writes. “Freed from the threat of defeat, this president will feel emboldened to double down on his worst impulses.”

A Warning, by Anonymous, Little Brown, RRP£20, 272 pages

Crime In Progress: The Secret History of the Trump-Russia Investigation, by Glenn Simpson and Peter Fritsch, Allen Lane, RRP£20, 368 pages

Ed Luce is the FT’s US national editor

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