As Robert F. Kennedy Jr. prepares to join President Trump's Cabinet, the rest of his storied political family has fallen far from its former glory.

President John F. Kennedy's only grandson, Jack Schlossberg, has brought shame on the Kennedy name with a series of juvenile rants online - leading one columnist to declare the return of the so-called "Kennedy curse" said to haunt the family.

In a scathing column for the Daily Mail, Maureen Callahan took 32-year-old Schlossberg to task for his vulgar and unseemly online statements - only for Schlossberg to target her in an unhinged post.

JFK's grandson brings shame

As of now, Schlossberg appears to have deleted his X account.

"I'm sorry to everyone I hurt. I was wrong," he wrote before deactivating. "I'm deleting all my social media. Forever. It's been fun. Thanks anyways everyone."

The dramatic move comes after a series of bizarre comments that caused a stir online.

In an Inauguration Day post, Schlossberg questioned whether Usha Vance, the wife of Vice President J.D. Vance, is more attractive than Schlossberg's own grandmother, Jackie Kennedy - a woman considered by many to be the epitome of class.

"True or False? Usha Vance is way hotter than Jackie O," he wrote.

The Kennedy scion later got wrapped up in a nasty feud with conservative media personality Megyn Kelly over the transgender issue, telling her, "Megyn Kelly can no longer play in female sports. You're welcome."

Spiraling further, Kennedy responded with a nasty slur to a takedown from the Daily Mail's Maureen Callahan, who called him an "underemployed manchild" as she accused him of reviving the "Kennedy curse."

"Sorry for the delayed response Maureen V***** ! Just seeing your message now. You can see my response on instagram..."

The black sheep rises... as a dynasty withers

This all comes as the former black sheep in the family, anti-vaccine activist Robert F. Kennedy Jr., is seeing his fortune turn for the better.

Long dismissed as a crank or conspiracy theorist, the ex-Democrat, who left his party to endorse President Trump's re-election campaign, is set to play a powerful government role as head of Health and Human Services after passing a Senate committee vote. It makes Kennedy the most successful member of his famously Democratic family since his uncle Senator Ted Kennedy, who died in 2009.

The term "Kennedy curse" was coined by Ted Kennedy, who plagued his family in scandal - and ended his own presidential hopes - when he notoriously left the scene of a fatal car accident that killed a young woman in Chappaquiddick, Massachusetts.

Last week, on the eve of RFK Jr.'s grilling by the Senate, his cousin, Caroline Kennedy - Schlossberg's mother - came out of the woodwork to attack him as a "predator," as Schlossberg called RFK Jr. a "guru shaman figure."

While the Kennedy clan is withering on the vine - except RFK Jr - many see Schlossberg's antics as a new low for the once influential family.

"I hope he gets the help he needs" RFK Jr.'s daughter, Kathleen 'Kick' Kennedy, told the New York Post.