Presidential campaigns are like fish: they rot from the head down.

At least that’s the view of the hired guns and political hacks who have toiled inside them and lost. So what happens when the rotten, stinking fish ends up winning?

Donald Trump’s clean sweep of the primaries on Tuesday night flies in the face of political fisheries. It also destroys his newfound political guru, Paul Manafort, who made the rookie mistake of trying to advise the candidate on, um, politics.

Manafort had the temerity to suggest that maybe now was the time to act presidential as the candidate was, you know, on the verge of seizing the presidential nomination. A political hack-turned-lobbyist for dubious countries, Manafort was promptly pushed overboard.

The candidate has taken to mocking his guru on the stump, refusing to perform the role of anything other than his current charming persona: the orange buffoon who can’t decide if he’s a genius or a thug.

This week he called one rival “a stubborn guy who eats like a slob” and his other rival “a pain in the ass”. Other people prefer to call them Governor John Kasich and Senator Ted Cruz.

“I am me,” he explained on Tuesday night. “It’s very easy to be presidential … Why would I change? If you have a football team and you are winning and you get to the Super Bowl, you don’t change your quarterback.”

Sure enough, Trump chose not to spend his victory night with supporters in a key battleground state. That would be too presidential for a candidate who says he considers himself the presumptive nominee.

Instead, he wooed his blue-collar voters by walking the red carpet at the Time 100 dinner in Manhattan, where he promised a big foreign policy speech and an inauguration party with Elton John as the entertainment.

If that doesn’t work, he could always get Elton John to craft his foreign policy.

Having read his foreign policy speech in full – or at least its executive summary – Trump gave us a glimpse of his worldview beyond the Great Wall of Mexico and a colossal trade war with China.

He informed us that, despite his obsession with Isis, the No 1 security threat facing the US was nuclear. Or as he called it, “the power of weaponry”. This is a useful concept in national security that man has perfected since the stone age. Weapons, especially destructive ones, can indeed threaten great countries.

China, he explained, has great influence over the weapon-filled state of North Korea. Trump’s genius idea is to get China to do something about the North Korean leader, whom he declined to name.

“We can’t let this guy go much further,” he said. Which is what the rest of the GOP has been saying about Trump for some time.

If the long presidential campaign tells us anything about a candidate’s character, the bizarre business of the 2016 campaign has told us this: Donald Trump is a man-child whose fingers are not the shortest part of his anatomy.

His victory speech consisted of taunting his former rivals and political pundits about the scale of his five wins on Tuesday. He called Kasich and Cruz “spoiled” for refusing to get out of the race, bragged about the bootlickers who were calling him up for jobs, and urged Bernie Sanders to run as an independent.

It wasn’t difficult to mock his rivals.

By the time Generals Kasich and Cruz carved up the continental United States of America, their forces were already routed by their arch-rival on the north-eastern seaboard. Admiral Trump called their treaty a failed deal made by politicians who were “all talk and no action”.

“They can’t get it done,” he said, as he lamented the trade deals that have helped employers outsource production to overseas companies. Instead, the man who outsourced his own clothing line promised he would make life impossible for outsourcing companies.

“I am going to represent our country with dignity and very well,” he told reporters in a makeshift news conference once his victory speech had run out of steam.

He then proceeded to call his Democratic rival “crooked Hillary” who didn’t have the strength or stamina to be president. Next he’ll accuse her of running like a girl.

If this is the presidential version of Donald Trump, this presidential candidate is beyond the reach of gurus and speechwriters. It’s time for Elton John to start rehearsing his requiem: Candle in the Wind.