Here in the States, where Thanksgiving is psychologically and politically on hold, it’s The Crown versus The Clown.

We’re living in an old-fashioned interregnum, that time in history when things could get dicey between the reigns of two monarchs.

Severed heads were often involved. We haven’t gotten to quite that stage, but it’s still early days.

So it’s telling that the brutal marital power struggle between Prince Charles and Princess Diana is so compelling right now – both as a nostalgia fix and a weirdly cautionary look at tradition, custom, power and norm-shattering.

Maureen Dowd in the New York Times points out the similarities between these two blondes.

Both lapped up their press and gabbed to favoured journalists. Both were unstable, paranoid and played the victim. Both wreaked havoc on the established order.

But Diana – even before her death made her a martyr – had demonstrated an exquisite sense of just how far to push both her family and the monarchy without disaffecting the people, who were her real source of power.

She may have been trashing her husband and in-laws in ways that were unseemly, but she was also breathing new life into an institution that was moribund and insensitive and hopelessly out of date.

She wasn’t anti-royal. She was just anti-Windsor.

Her self-absorption was epic, but either by design or default it always seemed to have others – AIDS victims, children – to take away the sting of her narcissism.

Donald Trump, on the other hand, is not the People’s President.

He’s no longer even paying lip service to the 70 million Americans who voted for him. And he certainly isn’t working his manic magic in an effort to bolster the foundations of American democracy.

Diana, we are reminded in The Crown, was born of the British aristocracy. In some of this season’s most compelling scenes, she is drilled on the minutiae of royal ways by her sourpuss grandmother, Lady Fermoy.

Emma Corrin plays Lady Diana Spencer in The Crown season four. Photo: Netflix

If only Mr Trump had been schooled in some similar way, to be awed and humbled by the power of the ideas behind what the founders built.

But Mr Trump has never shown the slightest interest in how this country works, what’s inside the Constitution, the mix of endurance and fragility that keep our institutions viable and respected. He is, for now, our Mad King.

In the years between her separation from Charles and her death, Diana managed to forge a new path, not quite a royal but not separate either.

She drew attention to her causes, cared for her sons, and managed to maintain her international celebrity.

She would turn 60 next summer. It’s hard to know how she would be seen had she lived, but both her legacy and the Windsors have managed to find a way forward, and endure.

Even Prince Harry and Meghan Markle figured out a way to wriggle away with some dignity, clearly looking to Harry’s mother as a guide to forging a post-Royal life that has some sense of duty among the creature comforts.

We Americans admire them for that, even though back home they’re still managing to frost the relatives.

Mr Trump will leave his self-styled throne with no such grace. It’s impossible to ignore his current scheming, but his tinfoil-hat claims of conspiracy are not driving supporters into the streets.

Some GOP members tut-tut his behaviour, suggesting it may soil his “legacy”.

Is there really anything left unsullied?

For all its sepulchral solemnity and Godfather-like set pieces, The Crown is a story about people whose fate, in the end, is of no great importance to the rest of us That’s why it’s such a cosy indulgence.

Alas, we don’t know how America’s monarchical mayhem will end. But we do know it has potentially great importance. So we need to keep watching, if only to make sure this season is its last.

Larry Hackett is the former editor-in-chief of People magazine, and a contributor to the US morning television news program Good Morning America