When former allies turn on one another, it is impossible to look away.

This is the No. 1 reason celebrity feuds always generate more gawking than celebrity friendships. Did you know Jimmy Fallon and Justin Timberlake are BFFs? Exactly. Yawn. You don't care. I don't care. Nobody cares. But if there was ever fallout and Timberlake started publicly trashing his erstwhile pal with outrageous claims — "Jimmy has sex with robots. Jimmy doesn't pay his taxes. Jimmy colluded with Russia. Jimmy does a perfect imitation of Ed McMahon's belly laugh after he kills fawns with a crossbow" — popcorn makers everywhere would explode from overuse.

What happened to those guys? They were BFFs! Man, this is great!

Which brings us to Donald Trump and his wildly entertaining new war with old friends. Imagine if Kim Kardashian and Kanye West had an ugly divorce. Or if the Hadid sisters got into a nasty brawl on a catwalk, pulling hair and accusing the other of a heinous betrayal. We'd be shocked — and enthralled.

It would be impossible to look away.

That's what is now happening as The Trump Show rumbles into 2019 with no scripts and several unforeseen villains. The president's safe spaces are shrinking. His favourite news network is starting to trigger him. Former stalwarts are morphing into trolls. Once reliable cheerleaders, convinced Trump's promised border wall is crumbling into a pipe dream, are chucking their pom-poms into a MAGA dumpster and calling their former hero everything from a "liar" to a "fool" to a "wimp."

And as they put up their dukes, the counterpuncher-in-chief is not having it.

Break out the kernels and the simulated butter.

On Sunday, Trump did something he does even less frequently than read an intelligence report or snack on kale: he criticized Fox News. It is impossible to overstate the importance of this crack in the universe. Since Trump won the Republican nomination, Fox has been his grinning wingman, giving a bedside thumbs-up as he dry-humped the truth or forced himself on alternate realities. If Trump ever declared patio furniture a national emergency, a Fox talking head could be counted upon to strongly agree: "Do we really want to make it easier for illegals to climb into our bedrooms? The president is absolutely right. Liberals should be ashamed for being soft on lanterns and hammocks."

But already reeling from the perception he just had his XXL boxers handed to him by Nancy Pelosi, Trump is in no mood for second-guessing, especially from former fellow travellers. So on Sunday, after watching a segment he did not immediately identify, Trump tweeted this: "Never thought I'd say this but I think @johnrobertsFox and @GillianHTurner @FoxNews have even less understanding of the Wall negotiations than the folks at FAKE NEWS CNN & NBC!"

Wow. Did he just rank-shift Fox News lower than CNN and NBC? Those are fighting words for this White House. The only way Trump could be more disgusted was if he compared Fox to the "failing New York Times," Amazon's Jeff "Bozo" or "pig" Rosie O'Donnell.

And if that tweet wasn't jarring enough, Trump is also fuelling a brouhaha with one of his earliest and strongest defenders. This weekend, when asked about firebrand Ann Coulter, who recently called Trump a wimp after he reopened the government without wall funding, Trump told the Wall Street Journal: "I hear she's become very hostile. Maybe I didn't return her phone call or something."

This is me slapping my forehead.

And putting Orville Redenbacher on auto-reorder.

Did Trump just dismiss Coulter the way a guy might shrug off a crazy ex? Is Trump not familiar with Coulter's capacity to inflict grave ad hominem harm on anyone who tangles with her in public? Whatever you think of her worldview, this woman is not screwing around when it comes to her hardline on immigration.

This is not a game for her.

And is Trump not aware and afraid of a potential domino effect? These are not fights he can win, mostly because these hilarious skirmishes threaten to create a supernova of layered feuds between his fed-up followers and those still fiercely inclined to defend him. This will only hasten a civil war on the right.

To understand what exactly I'm talking about, go read some of Coulter's tweets from Monday, including this one: "RIDDLE OF THE DAY: How do you break Newt Gingrich's nose? (ANSWER: Kick Donald Trump in the ass.)"

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I'll admit it: she kicked me in the funny bone with that one.

Watching Trump's former allies turn on him is shaping up to be the most entertaining show of 2019.

Vinay Menon is the Star's pop culture columnist based in Toronto. Follow him on Twitter: @vinaymenon

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