Michael Wolff’s new book, Fire and Fury, is an unforgettable ringside view of the reckless and undignified spectacle of the Donald Trump presidency so far. It will not surprise anyone that the US president comes across as a vain, delusional and unstable character whose public utterances could mostly be disproved by provable facts. Unable to master the presidential mien, Mr Trump has chosen to defile it. Without experienced advisers and consiglieres, Trump’s White House was divided into two camps: one led by his daughter, Ivanka, and his son-in-law, Jared Kushner, and the other by Steve Bannon, a Mephistophelian figure credited with channelling passions that more conventional politicians have been careful not to exploit. Mr Bannon, once Mr Trump’s chief strategist, is the book’s unkempt star. It is through his rise and fall that we learn how unsuited Mr Trump is to the world’s most demanding job.

Mr Bannon’s view is that Mr Trump is not likely to make it to the end of his first term. Either the president is brought down by the “treasonous” and “unpatriotic” meetings held by his son and a group of Russians or by federal prosecutors who unearth serious financial crimes. On this analysis Mr Bannon gave Mr Trump equal chances of staying in office, being removed by Congress or being declared mentally unfit for office.

The last option seems far-fetched, but the US constitution’s 25th amendment allows for a president to be removed if he is “unable to discharge the powers and duties of his office”. Such is Mr Trump’s divisiveness that a social movement of mental-health professionals has sprung up which argues Mr Trump suffers from incurable malignant narcissism and this renders him unfit for office. This is a break with conventions adopted in the wake of the failed rightwing US presidential candidate Barry Goldwater’s successful legal action against a magazine after it published a story in 1964 saying medics declared him so “severely paranoid” that he should not be able to become president. Since then psychiatrists have largely refrained from giving opinions about figures they have not personally examined.

It is a measure of how troubled the White House is seen to be that senior Republicans openly worry that the president is unravelling. Yet however erratic Mr Trump might be and however unsuited for high office, Republican voters remain loyal. Despite the rhetoric, Mr Trump’s base is largely made up of well-off and rightwing citizens rather than white, working-class voters struggling in a rapidly shifting global economy. This explains why his singular accomplishment, the Trump tax cut, will hurt poorer voters more than the Wall Street fatcats he railed against on the campaign trail.

Time will tell whether the details in Wolff’s book are completely true. Mr Trump lived up to his billing as a thin-skinned political neophyte by having his lawyer threaten the author with a lawsuit. If the government couldn’t stop publication of the classified Pentagon Papers, the US president certainly could not stop a book that offends no one but himself. Written without much hindsight and without access to official papers, Wolff’s tome is more than journalism, if less than history. He has collected raw gossip and spiky insights in the court of King Donald. Historians will make more authoritative assessments. Viewing events from a distance makes it easier to decide what is a chapter of history and what is a footnote. Fire and Fury is not the definitive book on the Trump presidency, offering instead a worrying glimpse of its chaotic early life.