WASHINGTON — Robert F. Kennedy Jr. says his presidential campaign is carrying on his famous family’s legacy. Some who revere that legacy fear he’s carrying it right off a cliff.

The 69-year-old environmental lawyer and antivaccine activist is waging a quixotic challenge to President Biden for the Democratic nomination. Polling usually shows his support somewhere in the teens, posing virtually no threat other than some mild embarrassment to Biden, despite some Democrats’ reservations about the octogenarian incumbent.

But the campaign has brought new and widespread attention to Kennedy, which in turn has elevated his conspiracy theory-laden views. Those include repeatedly debunked falsehoods and misleading statements about vaccines, public health, and about the assassination of his uncle, President John F. Kennedy. Each new comment has put an unwelcome spotlight on the broader family.

That was true again over the weekend when video from the New York Post surfaced of him claiming that the COVID virus is “ethnically targeted” to attack white and Black people, while “the people who are most immune are Ashkenazi Jews and Chinese.” Ashkenazi Jews are Jewish people of specifically Northern and Eastern European descent.

The remarks drew widespread condemnation as antisemitic and false, including from several members of his own family.

Two of his siblings specifically tried to distance his remarks from the legacy of their father, Robert F. Kennedy.

“I strongly condemn my brother’s deplorable and untruthful remarks,” Kerry Kennedy said in a statement as president of the nonprofit Robert F. Kennedy Human Rights foundation. “His statements do not represent what I believe or what Robert F. Kennedy Human Rights stand for.”

“Bobby’s comments are morally and factually wrong,” said Joseph Kennedy II, a former congressman and chair of Citizens Energy. “They play on antisemitic myths and stoke mistrust of the Chinese. His remarks in no way reflect the words and actions of our father, Robert F. Kennedy.”

Kennedy himself tweeted numerous defenses of his comments, including that they were intended to be off the record, misconstrued, and referencing a scientific paper, which analyzed theoretical genetic susceptibilities to COVID.

“This cynical maneuver is consistent with the mainstream media playbook to discredit me as a crank — and by association, to discredit revelations of genuine corruption and collusion,” Kennedy said.

He also brushed off the differences between him and his relatives in a statement provided to the Globe before his weekend remarks.

“Do you always agree with your extended family about politics?” he said. “We have our disagreements too, but we love each other as a family. I wish the same for the larger American family.”

Kennedy family members have repeatedly tried to distance themselves from Kennedy’s conspiratorial and antivaccine views. Last year, multiple family members, including his wife, actress Cheryl Hines, spoke out against him after he implied that people who oppose the COVID-19 vaccine are being persecuted more severely than Anne Frank, who died in a Nazi concentration camp. Kerry Kennedy also spoke against his views on vaccines and COVID in April, when his campaign launched.

Still, Kennedy is drawing heavily on his family name for his run, including direct appeals to the nostalgia of his uncles’ and father’s time in government and calling himself a “Kennedy Democrat.” The limited support he is getting is likely due in part to that existing goodwill.

The campaign is vexing some of the family, say those who know them, in no small part because of how central public health and vaccine access were to the Kennedy agenda, and particularly to his uncle Massachusetts Senator Ted Kennedy, who chaired the Senate’s main health committee and called health care “the cause of my life.” And there is fear that Kennedy’s run could tarnish the lasting image of the closest thing America has had to a royal family.

“It’s not good,” said Representative Stephen Lynch, a South Boston Democrat, in an interview before Kennedy’s latest remarks. “Everybody has a right to run, I guess. But this is not a good look.”

“His Uncle Teddy must be rolling in his grave over what this guy’s doing,” said Jim Manley, a former aide to Ted Kennedy, in an earlier interview. “It’s a repudiation of everything he worked for for years.”

Kennedy has had some success raising money, pulling in more than $6 million since announcing his bid, and has garnered some traction in the polls. But it’s unclear if the support would translate into success as a Democrat. Despite otherwise progressive views, especially on the environment, Kennedy has gotten the most attention from right-wing personalities and media outlets for his anti-establishment streak. House Republicans have invited him to testify at a congressional hearing on Thursday about alleged censorship.

Several of his biggest donors are noted vaccine skeptics, and analyses by Politico and Popular Info found significant numbers of his donors have historically supported Republicans.

Many of those who are close to or otherwise support the family’s legacy insist this presidential run won’t change it. Barney Frank, a former congressman from Massachusetts who served for decades alongside several Kennedys in Washington, said it was precisely that enduring brand which made Kennedy’s presidential campaign notable.

“Bobby Kennedy Jr. — that’s the bearded lady, the dog-faced boy,” Frank said in an earlier interview. “The attraction there is shock of things that aren’t supposed to go together — a right-wing Kennedy. So it’s not a serious issue, it’s kind of a ‘Ripley’s Believe It or Not’ section.”

The power of the Kennedy name has also been in precipitous decline at the ballot box for years. The family’s sprawling younger generation has suffered a string of campaign failures over the last two decades, including former representative Joseph Kennedy III’s unsuccessful 2020 primary challenge to Senator Ed Markey, a race the younger Kennedy lost by more than 10 points. The first loss by a Kennedy in Massachusetts since John F. Kennedy won a seat in Congress in 1946, the defeat halted the promising electoral career for the grandson of Robert F. Kennedy, who had been seen as the Camelot clan’s best hope for continued political relevance.

The younger Kennedy’s loss joined a slew of disappointments for the family including failed gubernatorial bids by Kathleen Kennedy Townsend in Maryland and Chris Kennedy in Illinois, a terminated Senate bid by Caroline Kennedy in New York, and a lost congressional campaign in Maryland by Mark Kennedy Shriver. Two other Kennedys, Joe Kennedy II and Patrick Kennedy II, served in Congress but ended their tenures amid personal difficulties.

“The magic of the name is gone even in Massachusetts,” said Laurence Leamer, author of three books on the Kennedys. “There’s some of it left, but it’s not what it was. ... If a Kennedy wins election, it will be because of his qualities and not because of his name from now on.”

The family has been mostly quiet about Kennedy’s presidential candidacy itself. Still, they have hinted about their stand on his campaign.

Five days after her brother launched his presidential bid and the statement she issued on behalf of the RFK foundation, Kerry Kennedy posted a picture on Instagram of Biden and Ethel Kennedy, the family’s current matriarch and Robert F. Kennedy’s widow. In it, Kerry recounted that on the way to Ireland with Joe Kennedy III, now Biden’s envoy to Northern Ireland, Biden and Joe had called Ethel from Air Force One to wish her happy birthday. The Instagram post emphasized numerous links and goodwill between Biden and the Kennedy family.

In addition to Joseph Kennedy III, three other members of the family serve in the administration, most notably Caroline Kennedy, John F. Kennedy’s daughter, who is ambassador to Australia, and Victoria Kennedy, Ted Kennedy’s widow, who serves as ambassador to Austria. No prominent Kennedy family member has endorsed Kennedy, and only a few relatives were at his campaign kickoff in Boston.

What remains to be seen is what comes next for the family, politically. Biden’s success in the Democratic primary over Kennedy is all-but assured with the full backing of the Democratic National Committee and the vast majority of the electorate.

Many observers wonder whether Joseph Kennedy III, at 42 years old, plans another political run, especially with burnished foreign policy credentials after representing Biden in Northern Ireland. The younger Kennedy did not respond to a request for comment on the topic, and several members of Congress who are still in touch with him said they have no inkling of what he wants to do next. They said he is engaged by his current work; all denied that his uncle’s presidential campaign would affect his future.

“Joe Kennedy has a bright, bright future, no matter what he chooses to do,” said Worcester Representative Jim McGovern, also a Democrat. “So I don’t think any of this detracts from that.”

Writers were eager to proclaim the end of the dynasty after Joseph Kennedy III’s Senate loss, and similar declarations were made in 2010 when the last Kennedy serving in office at the time stepped down.

How Robert F. Kennedy Jr. contributes to the legacy will be closely watched.

“It’s not how anyone would like to see the story end,” Leamer, the author, said. “No one wants to see the last chapter of the story to be him and his quixotic, dangerous campaign that could be the end of the Kennedys. None of the Kennedys want that.”

Tal Kopan can be reached at tal.kopan@globe.com.