So how is it that, despite the evidence of their own eyes, so many seem to support him - even to like and admire him? The answer is a worrying one for our (or at least for American) democracy.
The explanation is that the Donald Trump that most people think they know is a cipher, not a real person. He is a construct, created to function effectively only in the public and artificial domains of politics and television.
Trump made his reputation and created his persona as a television personality - a denizen of "reality" television who learned that he could entertain by shocking his audience and could arouse in some a reluctant admiration through his willingness to ride roughshod over anybody who got in his way.
The Trump people see on the stump as a presidential candidate is someone who is famous for his catch-cry, "You're fired!" They have grown accustomed to laughing and marvelling when the objects of Trump's brutal dismissals are discomfited and upset.
Sadly, they seem unable to distinguish between the qualities needed to entertain them on a television show and those required of a political leader who must strike a careful balance between competing interests both at home and abroad.
As someone who spent several years of his life as a reporter and interviewer on one of the UK's top current affairs shows, I recognise that there is a paradox here. It has always seemed to me that one of television's strengths as a medium is that, at its best, it quickly exposes anything that is false or a sham; the charlatan does not usually survive long.
But that depends on the public's ability to read what they see correctly. In Trump's case, they have learned, as they believe, to "read" him - and they willingly transfer what they think they have learned to the quite different context in which he now appears.
The Trump they see as a potential US President is, as far as they are concerned, "authentic". He is behaving as they expect him to. Behaviours that they would reject as inappropriate in anyone else - and certainly in any other candidate for the presidency - have been certified as acceptable by his success as a television personality.
The consequences of this unfortunate lacuna in public perception could be dire for the US and for the rest of the "free" world. And we would be foolish to assume that we are immune from the same syndrome in New Zealand.
We do not, mercifully, often have to reckon with television personalities seeking elected office. But we are not short of television "stars" whose stock-in-trade is relentless and shameless self-promotion and a readiness to insult, shock, and offend, and who, once having attracted a viewing audience, then take the chance to deliver us our current affairs along with an unhealthy dose of more or less overt and extreme political views.
Donald Trump is, in other words, not the only threat to an effective democracy. There are those everywhere, and not least here, ready to emulate what some would see as his "success".
