For decades, the Kennedys —  America’s so-called royal family — were known for politics, scandals and tragedies.

Nowadays, they’re developing a reputation for internal conflicts, with spiteful attacks against siblings and relatives, unusual social media outbursts, and revelations of longstanding personal disputes.

To defuse this embarrassing drama reminiscent of reality TV and unify the family before it disintegrates, Kerry Kennedy has secured what insiders describe as a seven-figure contract for a book honoring her mother, family matriarch Ethel Skakel Kennedy, who passed away last October at the age of 96.

This move is somewhat ironic since Kerry, the seventh of Ethel’s and Sen. Robert F. Kennedy’s 11 children, is one of the most outspoken figures in the family’s current public discord.

“Kerry’s well-varnished book will be little more than a last-ditch attempt to salvage the increasingly tarnished Kennedy name,” one insider told The Post.

Kerry Kennedy declined to comment.

Entitled “Ethel: Faith, Hope, Family, and an Extraordinary Life” and penned with a ghostwriter, the book is planned for fall 2026. Whether it can bring the family together, or truly spiff up their tarnished legacy, remains to be seen.

“Like the Titanic, the Kennedy brand is a sinking ship,” the insider said.

But, for all their talk about public service, the family’s battles are no surprise.

In fact, sources said, RFK’s staunchly Democratic widow, Ethel, who died of a stroke, would have “savored and enjoyed the very public attacks and controversy” involving some of her children — including the verbal assaults on Robert F. Kennedy, Jr. — when he briefly ran for president last year and later became Donald Trump’s Secretary of Health and Human Services.

At least some of the “attacks and snubs against Bobby Jr. were actually at the behest of Ethel,” alleged the insider. “She also was behind the photo [taken March 2024, just before RFK Jr. announced his presidential run] of three generations of her family with a smiling Joe Biden in their midst — all as a subtle [message] to Bobby. He was her least favorite son.”

It was alleged favorite daughter Kerry who, on her mother’s instructions, posted the photo on X, declaring of Biden, “You make the world better.”

In addition to six of RFK Jr.’s living siblings —  former Maryland Lt. Gov. Kathleen Kennedy, former US Rep. Joe Kennedy II, human rights activist Kerry Kennedy, filmmaker Rory Kennedy, lawyer Max Kennedy and businessman Christopher Kennedy — rebuking his presidential campaign by calling it “dangerous” and publicly endorsing Joe Biden, his cousin Caroline also made her feelings known.

Early this year, Caroline, now 67, and. the former US Ambassador to Japan and then Australia, wasn’t very diplomatic when it came to her first cousin, calling him a “predator” and hypocrite and unqualified to run HHS.

She also claimed: “Bobby expropriated my father’s image and distorted President Kennedy’s legacy to advance his own failed presidential campaign and groveled to Donald Trump for a job.”

Nonetheless, according to insiders, Caroline has been “virtually blacklisted” by some of her cousins over the bizarre social media postings of her son, Jack Schlossberg.

The 31-year-old has posted videos of himself making fun of RFK Jr.’s spasmodic dysphonia, a neurological disorder that affects his speech and which other members of the family may also have.

Schlossberg has also called the health secretary a “liar” and a “guru shaman figure who runs a cult” and taunted Vice-President J. D. Vance and his wife, Usha, joking about having a baby with her and writing, “True or false: Usha Vance is way hotter than Jackie O” — his maternal grandmother.

His various remarks prompted RFK Jr.’s daughter, Kathleen “Kick” Kennedy to previously tell The Post: “I hope he gets the help he needs.” 

Sources say Schlossberg’s behavior has led to Caroline — whose parents and brother are deceased — being completely isolated from the Kennedy tribe, which “is hurtful to her.”

The Post has reached out to Caroline for comment.

“Jack’s more Schlossberg than Kennedy in attitude,” a close source said, referring to Schlossberg’s father, the very private and eccentric artist and designer Edwin Schlossberg, 73, who comes from a prominent Jewish New York family.

Snarky Spy magazine once called Edwin “a well-to-do hippie-yuppie who’s self-consciously interesting… Camelot’s egghead-in-residence.”

Although little known publicly, the current feuds within the Kennedy family have a long history going back to Ethel and her late sister-in-law, John F. Kennedy’s widow, Jackie Kennedy Onassis, whom Ethel ruthlessly attacked.

“She thinks she’s a queen. When Jackie once mentioned she dreamed of being a ballet dancer, Ethel stared at Jackie’s slender size-11 feet, muttering to her face, ‘With those clodhoppers of yours? You’d be better off going into soccer,’ ” a source commented for my book “The Other Mrs. Kennedy: An Intimate and Revealing Look at the Hidden Life of Ethel Skakel Kennedy.”

Meanwhile, Jackie, sources added, considered Ethel “crude and boorish,” and referred to her as a “baby-making machine — wind her up and she becomes pregnant.”

Jackie’s revenge against the insults was to distance her own children, John Jr. and Caroline, from Ethel’s children.

When Ethel extended an invitation to her niece and nephew to stay for a couple of weeks at her family’s home Hickory Hill in McLean, Virginia, Jackie declared, “No way!’”

And through the generations the feuding continues.

JFK Jr. also got his digs in when he was founding editor of the political magazine George in the mid-1990s.

In a signed editorial, he pilloried his Kennedy cousins — Ethel’s sons Michael (who died as the result of a skiing accident in 1997) and Joe — as “poster boys for bad behavior” regarding their marital scandals.

While Kerry Kennedy’s planned book is said to paint her mother as a virtual saint, and the Kennedys as a close and loving family, an insider told The Post that “dysfunction rather than perfection” was a way of life for the late matriarch.

As Ethel’s fourth-born, David Anthony Kennedy, who died of a heroin overdose in 1984 at 36, once revealed, “Those stories about what a big, happy family we had at Hickory Hill were all bulls—t. Life at home was mayhem, a mess.

“My mother was always having screaming rages. The house looked like a shithole. She didn’t know how to deal with so many kids.”

A child-care sitter retained by Ethel once even admitted that the middle children — Courtney, David and RFK Jr. – “were virtually left to fend for themselves, with little or no supervision.”

The sitter also called Ethel a “distant, detached, and standoffish mother.

When popular Look magazine decided to do a cover story on Ethel, then pregnant, as the possible next future first lady when RFK began his ill-fated 1968 presidential run, the bi-weekly’s crack photographer-reporter team, Stanley Tretick and Laura Bergquist, were assigned.

The magazine ran an upbeat story, but Tretick and Bergquist were privately shocked by what they witnessed.

Tretick later revealed: “I never thought she was a great mother… The kids all went their separate ways. It was like bedlam, everyone running around crazy… one night Ethel was going to fix food for us, but she said ‘I don’t know how to fix s—t!’ She couldn’t handle anything in the kitchen. Bobby looked at her and said, ‘Mother of the year.’

“Our view of Ethel was, ‘God, it’s going to be bedlam, just nuts, if she goes to the White House, because that place will become a real zoo.’”