A TRAILER PARK CALLED CAMELOT:

Ethel was 40 and three months pregnant with her last child, daughter Rory, when her husband was assassinated. Bobby Jr. was 14, and one week after his father’s funeral, the family celebrated his brother’s 13th birthday. Bobby slipped laxatives into everyone’s drinks as a prank.

“Just leave home!” Ethel yelled at him. “Get out of my life!”

She often used such language with him. “Her moods could swing drastically,” Oppenheimer writes, and soon after, she “literally beat Bobby with a hairbrush.”

Unable to cope with her grief — let alone her children’s — Ethel shipped Bobby off to a series of boarding schools, each less prestigious than the last, each forced to expel the namesake son of a martyred political icon.

Bobby wasn’t even 15 and was already using drugs heavily. He insisted each school allow his pet falcon to stay in his room. He formed a gang, The Hyannis Port Terrors, and one of his favorite practical jokes was bumping the fender of a passing car, having a pal collapse in the road, then yelling, “You’ve killed a Kennedy!” He once spat in a cop’s face.

Ethel did nothing. She was sealed off in her McLean, Va., estate. Only her dead husband, his legacy and her privilege as a Kennedy widow existed. Nothing Bobby did got her attention for long, and that attention was usually negative.

“I never witnessed a civil conversation between Bobby and Ethel,” one of RFK Jr.’s ex-girlfriends told People in 1984.

When Bobby was arrested for buying pot in 1970, Ethel threw him in the bushes. “You’ve dragged your family’s name through the mud!” she yelled. . . .

In his 1994 biography of Ethel, “The Other Mrs. Kennedy,” Oppenheimer writes of her “uncontrolled rage” and the abuse that extended to her household staff. Her brother-in-law Peter Lawford was shocked when Ethel berated a new maid for going to throw out some old scraps of paper.

“You stupid n- - - -r,” Ethel yelled. “Don’t you know what you’re doing? You’re destroying history. Get out of my sight! You’re fired.”

One of Ethel’s secretaries, Noelle Fell, told Oppenheimer she was surprised by such outbursts.

“She would say things like, ‘Those black people are stupid,’ ” Fell recalled. “I really don’t think she liked blacks or Hispanics. She couldn’t stand it if they didn’t speak English.”

One such maid, who brought sanitary pads when Ethel asked for face cream, got a hard slap in the face. She quit on the spot.

Covered up by the press for decades, of course.