The duchess of Sussex, Meghan Markle, aspires to be “Angelina Jolie crossed with Amal Clooney squared with Princess Diana.” That observation was shared with members of The New York Sun by no less a figure than Tina Brown, the legendary editor.

“The realization that the Sussexes blew it is animating a lot of their rage,” Ms. Brown said in an on-stage interview with the publisher of the Sun, Dovid Efune, and your correspondent. “They’ve trashed the family,” she adds. Ms. Markle is “searching for her brand,” Ms. Brown said, and the Sussexes have made “every mistake” with respect to their royal exit. 

These remarks, and the one that Ms. Markle is “nothing like” the former princess of Wales, came at a Sun Founder member event at Lincoln Center. It was a lively conversation with a reporter who has raised up the monarchy’s story at a time of royal rupture. Ms. Brown, author of two deeply reported books on the monarchy — “The Diana Chronicles” and “The Palace Papers” — reflected for more than an hour on the state of the House of Windsor.

Ms. Brown sees “no resemblance at all” between Ms. Markle and Princess Diana, who was a “blue-blooded aristocrat” and who grew up in Althorp House and “got the whole royal thing” and “never would have left the royal family if Charles would have been in love with her.” 

Ms. Brown allows that both Diana and Ms. Markle possessed “greater charisma than the palace was willing to let them show,” and adds that it is “difficult to contain a star inside a hierarchy” as ancient as the royal family, which claims a lineage going back a thousand years.

The new sovereign, Charles III, was not, Ms. Brown observes, always “cut out for this job.” From the time he was in swaddling clothes he was “embalmed in duty,” both “lugubrious” and an “Eeyore.” Over time, though, Ms. Brown believes that his “passions and idiosyncrasies” have ripened, delivering a man ready to rule. Diana, she believes, “would have come around” to him as king.

The king’s subjects, Ms. Brown observes, are “bored” by Charles but “think he’s decent,” an emblem of stability after the hapless interlude of the “flyby prime minister,” Elizabeth Truss. He was “ahead of his time in his passionate belief that the climate is in danger,” an environmentalism now “in sync with the culture.”

Ms. Brown observes that the king “can’t be a campaigner, but he can be a convener” who is the “most senior statesman for his country.” The Foreign Office, she observes, considers him an “excellent diplomatic missile” in these uncertain post-Brexit days of Tory drift and discontent.

Of the Sussexes, Ms. Brown notes that “they have made every mistake in terms of how they played their desire to exit the royal family.” She reports that one of their entourage told her that “Harry and Meghan are addicted to drama.” The duke of Sussex saw Ms. Markle, she reckons, as an “exit strategy” because of her “worldly grasp of things like Netflix.”

Ms. Brown admits that “it is not pleasant to marry into the Windsor family,” but that of all the candidates to do so, Ms. Markle was “the worst.” The duchess of Sussex “thought she was going to be living in Windsor Castle being Angelina Jolie” but instead goes to “cheesy charity events with red carpets. That has left them furious.”

Ms. Brown judges the Sussexes to be caught in the throes of “victimology” and ensnared in an “us against the world” mindset and afflicted with “FOMO,” or the fear of missing out. It would “not be hard for Harry to win back the British public,” Ms. Brown reckons, but “they are hoping he one day will come back without Meghan.”

Even though Ms. Brown believes that the Sussexes have thrown “so many bombs it’s going to be five years before somebody believes them again,” she calls Meghan and Harry “more sexy, more modern, and more interesting” than the Waleses, William and Catherine. The Sussexes, though, have “trashed the family,” leaving them on the outside looking in.

Ms. Brown, who edited the Tatler, Vanity Fair, and the New Yorker, and founded and edited the late Talk magazine and the Daily Beast, calls Harry’s memoir, “Spare,” a “rip-snortin’ good read” that more than earned him the nickname “Harry the hand grenade.” Finances, she predicts, will drive a book from Ms. Markle in the near future, “out of necessity.”  

Calling the monarchy a “slightly moldering studio system in which everyone jostles for the most attention,” Ms. Brown insisted that Queen Elizabeth II saw early on that Ms. Markle would be the “same kind of irritant that Princess Diana was,” though the late princess “spent 17 years being exemplary” and would have been pained by her son absconding from his royal duties and his destiny.

There is, Ms. Brown asserts with sympathy for the Sussexes, a “deep state of the palace filled with claustrophobic and prancing courtiers that any virile or robust person would find deeply irritating.” Not helping matters is a retinue of “dripping debutantes.” 

Turning to the future of the monarchy, Ms. Brown notes that “the most powerful woman in the royal family right now” is the princess of Wales. “It all hangs on Kate,” she ventures, as the effects of any discord between her and the heir to the throne would be cataclysmic to the standing of the royals. She warns that the “monarchy is way more fragile than it has ever been.”