It has been a busy few days for Donald Trump. A new attorney general here, a new UN ambassador there. All that legal stuff about his felonies in the 2016 election and “synergy” with the Russian government.

What’s a guy to do?

Fire someone, obviously. If there’s one thing Trump knows how to do, it’s pretending like he knows how to wield power in front of the gawking media. It worked pretty well on The Apprentice, projecting the image of power on to the boss of a small-time real-estate business with multiple bankruptcies.

But at this mid-life crisis stage of a catastrophically doomed presidency, there aren’t that many people worth firing any more.

So it came to pass that John Kelly found himself dumped on the Trump sidewalk of history, a throwaway tidbit of news in a dumpster fire of calamities. Trump’s face-palming chief of staff was just another casualty of this president’s dismal need to destroy the reputations of those who come too close.

“John Kelly will be leaving,” he told reporters on the South Lawn of the White House before flying off to see the Army v Navy football game.

“I don’t know if I can say ‘retiring’,” he explained, slamming the door into Kelly’s back as he shoved him out of the West Wing. He couldn’t say retiring and he couldn’t say firing. Either way he said both, in passing, and without the man present to witness his own humiliation.

As staff send-offs go, this was somewhere below a farewell cupcake but one notch above being frog-marched out

Trump said his non-retiring chief of staff was “a great guy” but only managed to offer up this tepid testimonial to a former four-star marine general who was the most important staffer in his White House: “He’s been with me almost two years now.”

As staff send-offs go, this was somewhere below a farewell cupcake but one notch above being frog-marched out.

It seemed like a fitting end to a week in which Trump had finally reached the 15th time when he finally looked presidential. This week’s episode in Trump Behaving Boringly featured a silent president sitting sullenly in the pews at the funeral for President George HW Bush. His claim to greatness was that he failed to projectile vomit through the proceedings, although at times it looked like he wanted to.

Until now, the working hypothesis about Trump’s constant media craving is that he’s engaged in some sophisticated game of distraction. As Robert Mueller’s investigations close in on the many criminal conspiracies surrounding his business affairs and the 2016 election, Trump needs to flash something bright and shiny to keep our attention away from his latest epic failure.

However, Kelly’s firing underscores a different motive. Trump is increasingly impotent with each passing week, with each new legal filing, with each new revelation of another former loyalist’s betrayal. He just lost the House to his arch-enemies in a political landslide, and a new era of investigations is almost upon him. Within weeks the fickle media’s attention will shift sharply to a sprawling cast of Democrats who want to push him out of the White House.

If he can’t stop the investigations, can’t pass any legislation and can’t yet run for re-election, all he can do is cling to the impression of power. Shuffling his staff is just another arrangement of deckchairs aboard an ocean liner already heading towards the sea floor.

This explains Trump’s strange morning habit of revisiting the scenes of his favorite firings and ritual humiliations. Like the home-made shrine of a serial killer, Trump’s Twitter feed relives and repeats the moments of what feel to him like his greatest domination.

On Saturday it was Richard Blumenthal, the Connecticut senator, who dared to call Trump “an unindicted co-conspirator” on national television. Trump responded by calling Blumenthal “Da Nang Dick”, an apparent reference to his Vietnam service at home in the Marine Corps. Never mind that both of them contrived to get five deferments from serving on the battlefield.

On Sunday it was James Comey, the former FBI chief whom Trump fired for digging around all things Russian. “Leakin’ James Comey must have set a record for who lied the most to Congress in one day,” Trump tweeted. “His Friday testimony was so untruthful! This whole deal is a Rigged Fraud headed up by dishonest people who would do anything so that I could not become President. They are now exposed!”

Self-awareness is not among the most obvious traits of Donald J Trump. His personal fixer just pleaded guilty to lying to Congress to protect Donald J Trump, while prosecutors described his criminal role in secretly paying off porn stars in terms that sound remarkably like a “Rigged Fraud”.

Unlike with Blumenthal and Comey, Trump has “no plans to humiliate” his chief of staff, according to Trump officials who obviously have no recollection of the many months of Trump’s open musings about firing Kelly.

In any case, Kelly – like so many others – has already humiliated himself by enabling an incompetent and autocratic president while pretending to restrain him. The self-made myths of Kelly and his delusional clan are that they were the last defense against Trump truly damaging the US and its national security.

As if there were no damage from the deaths of thousands of Americans in Puerto Rico after Hurricane Maria, or the forced separation of several hundred infants from their parents at the southern border, or the presidential sympathy for neo-Nazis, or the destruction of jobs in a futile trade war with China, or the weakening of alliances in pursuit of Vladimir Putin’s approval. As far as we know, Kelly personally supported several of those approaches, especially draconian restrictions on immigration.

Trump may have no current plans to humiliate Kelly but sooner or later he’ll find he just can’t help himself. He called his last secretary of state, Rex Tillerson, “dumb as a rock” and “lazy as hell”. This from a president who doesn’t read, spends his time tweeting about TV and just named a former Fox News anchor to be UN ambassador.

You have been warned, John Kelly. Trump’s mojo stopped working a long time ago, but he still thinks it works on you.