Observers cite voter anger at an entitled political establishment and an ever-wealthier and privileged elite; gridlock and dysfunction in Washington; international tensions; and economic dislocation and distress to explain his victories in the primaries and now in the general election.

They’re not wrong. Over the course of the campaign, Trump threw fuel on all these hotspots. Still more critical to his success, he nailed the white male support that would put him over the top in electoral votes on by his continual attacks on the legitimacy of the nation’s first African-American president, his targeting and denunciation of undocumented immigrants and Muslims, and his overtly sexist remarks about women.

But after writing a book about Donald Trump, his father, and his grandfather, I think other factors played a pivotal role.

For starters, there’s a Trump family culture of ruthlessly pressing any advantage, stretching the truth, and pushing the legal and ethical envelope to the max. Trump’s German immigrant grandfather, who operated restaurants in Gold Rush-era Seattle and the Yukon, amassed a nest egg by offering miners alcohol, food and proximity to women; his father greatly increased the family fortune by exploiting loopholes in New Deal government subsidies he tapped to construct middle-income housing in Brooklyn and Queens; and Trump used a billion-dollar loss of borrowed money and four corporate bankruptcies to build a global brand and avoid paying personal income taxes for nearly two decades.

That family culture also includes an adherence to the success-oriented theology of Dr Norman Vincent Peale, author of the 1952 bestseller The Power of Positive Thinking. Peale was the pastor of Marble Collegiate Church, where Trump’s parents attended services, where Trump and his sisters married, and where funeral services for their parents took place. In his book, Peale emphasises the supreme importance of self-confidence, a notion that Trump has not merely embraced but weaponised with a winning-at-all-costs, scorched-earth approach that has more than fulfilled his own father’s fierce injunction to be a “killer” in every pursuit. Among many results are a remarkable litigation history – according to USA Today, as of mid-2016, Trump had been involved in more than 3,500 lawsuits, including dozens that are still active – and a political campaign characterised by an unprecedented level of venom and vitriol.

But Trump has also contributed his own special flourishes.

Linguists found Trump was second only to Hillary Clinton in terms of how feminine he sounded

For example, his much-ridiculed hair. For years it has been a highly effective trademark, a humanising bit of vanity that made him the people’s billionaire, rather than a remote tycoon, and on the campaign trail, his coiffure made him the perpetual centre of attention. As with the traditional circus clown’s big red nose, Trump’s bouffant blond combover cued audiences that at any moment he might do something entertaining, and that it was permissible to laugh, even cheer, if some sort of antisocial activity occurred.

For a clown, this includes antics like hitting people with a baseball bat or dumping water on their heads; for Trump, it was likely to be a vicious taunt, a preposterous exaggeration, even a suggestion to rough up protesters, behaviour that would ordinarily be considered unacceptable but was now tolerated, even celebrated, because it could be explained away as “only” a performance, a joke, or – one of Trump’s favourite phrases – “truthful hyperbole”.

Ultimately, however, Trump’s success may have hinged on his voice. “I am your voice,” he declared in his acceptance speech at the Republican National Convention in July -- and there is more to that claim than might have been apparent at that moment.

Let me lay it out. Curiously, despite his obsession with showing that he is the most powerful person on earth, his speech doesn’t have the archetypal tough-guy edge.

In part, this is because, as the New York Times reported during the primaries, linguists found he was the second only to Hillary Clinton in terms of how feminine he sounded. Moreover, when measured by non-verbal cues like gestures, facial expressiveness, and statements posed as questions, he came in as the most feminine of the entire field.

But, perhaps even more importantly, it is also because of the way he sounds. Although he’s shown he’s more than capable of shouting in classic rabble-rousing style, more often than not what comes out when he opens his mouth is not traditional alpha-male talk. In contrast to both the hyper-belligerence of Jean-Claude Van Damme and the chilling rasp of Clint Eastwood, Trump’s speech tends to be in the middle range, even slightly high pitched – not effeminate but, despite his guarantee in one debate as to the adequacy of his genital endowment, not testosterone-laden either.

This low-key verbal tone might seem unimportant. At most, a meaningless distinction overshadowed by his relentless aggression and braggadocio. In other words, not a big deal.

But its effect is a big deal. Instead of insistently bellowing or pounding his chest like an Arnold Schwarzenegger, he’s tapping into a different stereotype: the counter-intuitive strongman who tosses off some of his most devastating comments with a malevolent sneer. Think Marlon Brando or Robert de Niro, who make their point not by shouting they’re going to blow your head off but by hissing that you’d better cooperate if you want to see another sunrise.

Moreover, Trump’s speech is hardly bristling with complexity. Rather, his vocabulary is extremely simple, almost to the point of being childish, and his use of incomplete thoughts and sentence fragments has an unmediated, stream-of-consciousness feel.

It is this combination – the hint of menace beneath the surface added to what appears to be an unpolished immediacy – that millions of listeners take as evidence of Trump’s authenticity and spontaneity. Indeed, the way he talks reminds them of the voice inside their own heads – a rich and sometimes dark stew of conversational snippets and memory scraps, random phrases and half-thoughts – and, by extension, it somehow seems as if they’re hearing the voice inside his head.

To many, the way Trump talks has been evidence of his lack of seriousness, of focus, of discipline, especially compared to Hillary Clinton’s thorough, detail-oriented explanations of her programmes. But to his supporters, it is proof positive that he is the real deal – not focus-grouped, not mediated, not hiding behind a mask of calculation and manipulation. For fear of censure, they keep their own interior voice, mostly banal but sometimes ugly, in check, but they admire and, in some cases, envy Trump for openly expressing a deepest self that seems to mirror what they think and feel but don’t dare reveal to the world.

Further, with almost uncanny timing, Donald Trump launched his presidential candidacy at a moment when technology provided him with the perfect megaphone for his verbal style, in the form of Twitter. Its 140-character limit reinforces the sense of urgency and genuineness, the impression of seeing directly inside his head and glimpsing unfiltered, unvarnished sentiments and emotions. Even more than the substance of his words, it is the apparent immediacy, even intimacy, of this inner voice that makes his denunciations of “political correctness” strike such a powerful chord.

In fact, there is nothing authentic or spontaneous about what Donald Trump says; everything is considered, strategic, and, as even a casual look at his rallies on YouTube reveals, repeated continually. Nonetheless, this impression of having a direct line to what he’s actually thinking is proof to his supporters of his underlying honesty – and as such, a vital clue to understanding how it is that this man, the most artificial of creatures in every possible respect, from the blow-dried effusion on the top of his head to the gilt coating that covers every available surface in his 53-room penthouse on Fifth Avenue, has come to represent “telling it like it is” to enough voters that he is now the president-elect of the United States.

This is an expanded version of the preface for a new edition of Gwenda Blair’s book, The Trumps: Three Generations of Builders and a Presidential Candidate