To quote the philosopher Peggy Lee, is that all there is? Having waited for Melania Trump to take the stage at the Republican convention in Cleveland, Ohio, one expected a little more than a tinny blast of We Are the Champions and a measly row over plagiarism (which the Trump camp denies). She might at least have worn Republican red feathers and a hula-hula skirt. Was this really the 5th Avenue Caesar’s missus, the wife of the biggest political blowhard of the age?

Usually, the world gets a little more than it bargained for when it comes to Donald Trump. Expect a coherent immigration policy and he will blow your mind with his deportation plans, a ban on Muslims entering the US, and blueprints for a wall between Mexico and the US. Still, it is early days, convention-wise. The candidate will deliver his speech on Thursday evening, an event scheduled for prime-time America, middle of the night for the rest of us. Like the Brexit vote, we will wake up to it. What can we expect? Indeed, if the Republican hopeful continues to defy all laws of political physics and makes it all the way to the White House, what will a Trump presidency look like? What will he do with the most powerful job in the world?

Such questions are surfacing as never before as November 8 approaches. Like people who have laughed themselves sick over a joke, the gap between the chuckles is growing longer; reality is returning. As the young folk would say, and I paraphrase, stuff just got real.

What is remarkable thus far is how Teflon the Donald has turned out to be. Nothing appears to faze or embarrass him or his camp. The Melania speech is a case in point. Another candidate, say a Joe Biden, once caught using Neil Kinnock’s lines, would have apologised for any muddle, and, in time, made a joke of it. With the Trump camp? An acknowledgment that Melania's team of writers “took notes on her life's inspirations, and in some instances included fragments that reflected her own thinking”. Kiddies, remember that one if ever you are caught copying homework. “I didn’t cheat Miss, I merely included fragments from Jimmy’s homework that reflected my own thinking.” Whatever the story is, Mr Trump’s utter shamelessness swallows it in one gulp, so that all one remembers is his chutzpah rather than the transgression.

Look closely, however, and there are gaps in the armour. Whether many are noticing them is another matter, but they are there. A compelling portrait of Mr Trump emerged this week in The New Yorker. It stems from an interview with Tony Schwartz, who was Mr Trump’s ghostwriter for his business memoir The Art of the Deal. This 1987 book has arguably been as helpful to Mr Trump’s ascent as his dad’s initial “small loan” of $1 million. After all, it was Art of the Deal that created the legend of The Donald as a man who Got Things Done. From this flowed more money, a TV career, and so on until the present day when he is a participant in the ultimate reality show, a run for the White House. And it was Schwartz who ghosted it. As a publisher tells the writer of the piece, Jane Mayer, “Tony created Trump. He’s Dr Frankenstein.”

What does the good doctor, then, think about his creation now? “I put lipstick on a pig,” he told Mayer. “I feel a deep sense of remorse that I contributed to presenting Trump in a way that brought him wider attention and made him more appealing than he is. I genuinely believe that if Trump wins and gets the nuclear codes there is an excellent possibility it will lead to the end of civilisation.” If the book was written today, he added, he would call it The Sociopath. All together now: Ooft.

Mr Trump poo-poos Schwartz’s role in the book, insisting that he, Donald Trump, wrote it, and he has accused Schwartz of “great disloyalty” because he made him rich. The book has indeed been a lovely little earner for Schwartz (half the royalties and advance), so his contrition has to be taken with a cellar full of salt. Even so, the image he presents of a man who lacks concentration, who deals with issues in soundbites, who has no shades of grey, is as scary as a Boris Johnson premiership (best not speak too soon…).

It is only concerning, however, if one believes his policy choices would be disastrous if he became president and was given the chance to implement them. But aside from his immigration policies, his ban on Muslim visitors and the wall, what do we know of the Trump manifesto? While that might sound like a Mrs Lincoln question (“Apart from that, how did you enjoy the play, Mrs L?”), it is worth asking if only to highlight how much of an unknown quantity this man is, how he has come this far without his ideas seeing the light of day, never mind being tested. Why, anyone would think the hoopla that surrounds him was a way of hiding the fact he has no policies. Anyone would be right. But can he carry on as the candidate lite? At what point is the curtain torn aside, and if it is not, how much trouble might the world be in?

A Donald Trump writing this – he wrote the Art of the Deal, remember – would have an answer to all those questions. Making America Great again is his big idea he would say, and that is a tried and tested, American classic formula for governing. If in doubt, put America first. Trade? American jobs first. Foreign policy? American interests first. The details are for another day, just leave it to Donald.

There is still hope. Mr Trump can play safe when he needs to, as evidenced by his choice of steady-as-he-goes Indiana Governor Mike Pence as running mate. More importantly, there is a limit to how much anyone in the job can do. When one looks at American government in the modern era the one abiding lesson is that it is toweringly difficult to get anything done. Ask Mr Obama. It is possible to engineer a modicum of radical reform, as he did with healthcare, but stage a revolution? America has been there, done that, and learned the lessons accordingly. There is method in what sometimes seems like madness. There is history. One of the first tasks undertaken by a country that was built in opposition to monarchy and rule by diktat was to make sure such things could not happen again, that the republic would not come under the sway of a demagogue. Power was separated between the executive, the judiciary and the legislature the better to preserve a balance, to keep checks on the mighty.

All of which is fine and dandy with domestic policy; foreign affairs is another matter for another day and another nightmare. Still, come Thursday evening, Mr Trump will have nowhere left to hide. There will be no ghostwriter up there with him. Only he can do the deal now.