“A smart boy and a bad influence.” That is how Robert F. Kennedy Jr. is described by Martin Peretz, the former owner of the New Republic, who taught Kennedy at Harvard. Mr. Peretz’s new memoir, “The Controversialist,” reports that Kennedy’s best friend at Harvard was Eric Breindel, who went on to become the brilliant editorial page editor of the New York Post.

“Eric liked the Kennedys, he was drawn to them, and he and Bobby Kennedy became drug mates at Harvard,” Mr. Peretz writes. Norman Podhoretz, the former editor of Commentary, was quoted in New York magazine after Breindel’s death in 1998 at age 42. Breindel “was mixed up with the Kennedy kids Bobby and David, and they were junkies,” Mr. Podhoretz said then. David Kennedy died in 1984 at age 28; that same year, Bobby Kennedy pleaded guilty to a heroin possession charge.

Breindel had been arrested in 1983, while a staff member of the Senate Intelligence Committee, on a misdemeanor heroin-related charge.  When Mr. Peretz and his then-wife Anne threw a graduation party for Breindel, “one of Bobby’s cousins, Maria Shriver, began to carve her name onto our eighteenth-century dining room table until Anne caught her at the task.”

The Peretz memoir reports that, “Caroline Kennedy, Eric’s one-time girlfriend, whom I liked, was watching this cousin do the carving, and Caroline looked so embarrassed. But for some reason, she didn’t stop her.”

This time around, with Robert F. Kennedy Jr. challenging President Biden for the Democratic presidential nomination, the Kennedy relatives are at least making a show of trying to stop their relative before he does damage. 

Caroline Kennedy’s son, Jack Schlossberg, recently posted an Instagram video denouncing his cousin. “He’s trading in on Camelot, celebrity, conspiracy theories and conflict for personal gain and fame,” Mr. Schlossberg says in the video. “I know him. I have no idea why anyone thinks he should be president. …His candidacy is an embarrassment. Let’s not be distracted again by somebody’s vanity project.” 

Mr. Schlossberg instead endorses Mr. Biden: “He’s appointed more federal judges than any president since my grandfather….” Not accurate, according to the counts maintained by the administrative office of the United States Courts. 

Mr. Schlossberg has plenty of company in the Kennedy family in denouncing RFK Jr. His sister Kerry Kennedy issued a statement that said, “I strongly condemn my brother’s deplorable and untruthful remarks last week about Covid being engineered for ethnic targeting.”

RFK Jr.’s  brother Joseph Kennedy II told the Boston Globe, “Bobby’s comments are morally and factually wrong. They play on antisemitic myths and stoke mistrust of the Chinese.”

Mr. Kennedy is forging ahead regardless. A Harvard Harris Poll fielded July 19-20, 2023 found him with a remarkable 47 percent favorable rating and 26 percent unfavorable rating, the highest positive spread of any political figure polled. He is scheduled to participate in a July 25 Town Hall hosted by Fox News’s Sean Hannity and, also that day, to appear with Rabbi Shmuley Boteach “to discuss fighting antisemitism and championing Israel.” 

At best, a politician who conquered drug addiction and saw the damage it wreaked might be precisely what is needed to help a country still grappling with opioids and fentanyl.

At worst, though, Mr. Kennedy, who made a career as a conservation activist, shows the environmental movement at its paranoid worst — indulging sweeping and unscientifically negative conclusions about one chemical after another. 

Mr. Kennedy’s choice of far-left Dennis Kucinich as his campaign manager doesn’t exactly inspire confidence, either. New York magazine quotes Robert F. Kennedy Jr.’s remarks at Breindel’s funeral, which took place at Park Avenue Synagogue. It said Mr. Kennedy talked about loyalty. “I come from a family that puts a high premium on that virtue,” he said.  

Mr. Kennedy’s family members seem to be interpreting “loyalty” as fidelity to Joe Biden rather than to their family member who is running for president. If the rest of the Democratic Party follows that pattern, perhaps Mr. Kennedy will seek an alternative route to the White House as an independent, or as Donald Trump’s vice presidential candidate.

Or perhaps a Biden health deterioration could lead to a pre-primary withdrawal, positioning Kennedy as the next Democrat in line. 

What, in any event, does Kennedy make of Eric Breindel’s editorial legacy, at the New York Post, of having helped to usher in the Giuliani-era revival of law and order in New York City?

If Robert F. Kennedy Jr. is indeed as smart as Mr. Peretz suggests, it could yet turn out that the most significant and still promising thing is not Kennedy’s influence on Breindel, but Breindel’s influence on Kennedy.