That old line that “politics is showbiz for ugly people” is so good it should be true, but it isn’t really. Politics has always been politics, and showbiz is something different. Not, however, in the unique case of Donald Trump. The current US president is best understood as a pomp-era megastar. Extraordinary, really, that Trump never even needed to get into cocaine. I think when he dies scientists will discover that his body naturally produced coke as a byproduct of digesting overcooked hamburgers.

Everything he says or does is redolent not of a politician, but an ego-driven entertainment industry behemoth. Monday afternoon in Egypt, with all the awkward world leaders box-stepping behind him, was very much The Official Release Party of a Peace Process. Ego can, of course, be very creative, so it should be widely acknowledged that this hold-your-breath settlement simply couldn’t have happened without our leading man.

In recent years you may have read whole screeds on “the Trump doctrine”, often written by former foreign ministers or revered diplomats, which singularly fail to capture the essence of the entity with which they are dealing. Maybe the reason they seem to have had so much trouble codifying things convincingly is that most of these people either regard showbiz as beneath them or know slightly less about it than they do about some obscure branch of theoretical chemistry. The muddle they get into is trying to compare and contrast Trump with Henry Kissinger or Benjamin Franklin or a pick-your-20th-century Euro-dictator, when it should obviously be Elizabeth Taylor or actual Taylor or turbo-monster-era Led Zeppelin.

The category mistake is even more perplexing because Trump makes his essential star-based ethos very clear. He speaks constantly about his ratings, releases the equivalent of political diss tracks twice a week, is pathologically allergic to anyone having more attention than him, has a genius for staged events and subsumes team efforts wholly into himself. He is solipsistic, unpredictable and easily bored – all of those both innately and tactically. Showbiz monsters are both born and made. What we saw in Israel and Egypt yesterday was the modus operandi of a megaceleb in their most impossible-to-say-no-to era.

It’s notable that in an age where the most constantly eulogised celebrity quality is “authenticity”, Trump is a politician about whom no one ever says: “Yeah, but what does he actually believe?” It’s all right up there on the screen. You’re watching it. There aren’t really methods, or if there are, they are underpinned by the anti-philosophy that the first part of the word method is “me”. Everything he does, including the current ceasefire and peace plan, flows from the distinctly starry practice of having people bring him projects, which will get made only if his name becomes attached.

And people bring him all kind of projects – international hotel developments, peace processes, fragrance lines. All of them become what Hollywood would call “a Donald Trump vehicle”. There might well be merchandise associated with this ceasefire if it holds and develops. Following the assassination attempt on him last year, Trump released a Fight, Fight, Fight fragrance, which is forever selling out on his website. Don’t rule out some kind of Peace Through Strength aftershave hitting the online shelves soon.

Few megastars still do things solely for humanitarian or artistic reasons. Commerce becomes a way of keeping score, and plays a larger part. I somewhat suspect Blake Lively declared legal war on Justin Baldoni when she was able to gauge how much an alleged covert smear campaign was affecting her commercial image via plummeting sales of her new haircare line. Taylor Swift went nuclear on Katy Perry when the latter tried to hire some of her backing dancers – or, as Taylor saw it, “basically tried to sabotage an entire arena tour”. It’s difficult to get past the sense that when Trump moved on this peace deal, he did so for selfish ones. Commerce is his special place, and you’d better not touch it without consent. In the case of Qatar, where the Trump family organisation had just done a $3bn deal to build a luxury golf resort, you’d certainly better not misfire some missiles in there. How dare you, Bibi?!

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As I say, this kind of ego can produce some great material. The bit in Monday’s Knesset speech when Trump “went there” on Netanyahu’s much staved-off fraud and bribery trials was one of the most hilarious friendly drive-bys you will you ever see in politics, and very difficult to greet with anything other than an involuntary laugh of disbelief. “Give him a pardon, come on,” Trump digressed. “Cigars and champagne, who the hell cares about that?” Amazing.

With that photocall in Egypt, we are now encouraged to think Trump has entered his peacemaker era. In fact, I know they’re not each other’s biggest fans, but the thing I’ve seen recently that it most reminded me of was Taylor Swift’s album film, The Official Release Party of a Showgirl, whose centrepiece is the making of a video. Swift is shown constantly turning up when all the other creatives have presumably been on the process for weeks or months, coming up with thoughts they all treat like strokes of genius. Every one of these ideas conveniently ends up being adopted. Could they really all be credited to her? That is certainly the impression the director – a Ms Taylor Swift – gives us.

I imagine the White House works a lot like this. Actually, I don’t need to imagine it. When he missed out on a certain Norwegian award last week, a White House spokesman pulled a full Kanye-interrupting-Taylor-at-the-Grammys move, declaring furiously: “He has the heart of a humanitarian, and there will never be anyone like him who can move mountains with the sheer force of his will.” Well, there’s always next year, by which time we could well be in new acronym territory. A whole 21 stars have an Egot (Emmy, Grammy, Oscar, Tony). But only one is gunning for an Egont.

• Marina Hyde is a Guardian columnist

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