Speaking at a festival hosted by a libertarian group in New Hampshire, Robert F. Kennedy Jr. railed against the “mainstream media” for serving as “propagandists for the powerful.” Each time he mentioned the perfidy of the press — for silencing dissent, for toeing the government line, for labeling him a conspiracy theorist — he drew a supportive hail of jeers.
It was a page out of the playbook of Donald J. Trump. But for Mr. Kennedy, who is running a long-shot challenge to President Biden for the Democratic nomination for president, it was more than a rhetorical flourish.
Censorship is a central theme of his campaign, uniting an unlikely coalition that includes longtime acolytes in what is known as the “health freedom” movement; donors from Silicon Valley; and new admirers from across the political spectrum.
“The mainstream media that is here today is going to report that I, you know, have paranoid conspiracy theories, which is what they always say, but I’m just going to tell you facts,” Mr. Kennedy said at the event last week. He added, “When the press believes it is their job to protect you from dangerous information, they are manipulating you.”
Indeed, Mr. Kennedy, an environmental lawyer and scion of the storied Kennedy Democratic clan, is now a leading vaccine skeptic and purveyor of conspiracy theories. He has twisted facts about vaccine development by presenting information out of context; embraced unsubstantiated claims that some clouds are chemical agents being spread by the government; and promoted the decades-old theory that the C.I.A. killed his uncle, former President John F. Kennedy.
The idea that the press has a stranglehold on public information is a core, animating belief in the health freedom movement, which broadly opposes regulation of health practices, including vaccinations. Two political action committees supporting Mr. Kennedy were formed by people who knew him through this movement, which accounts for some of his most ardent support.
Censorship, and specifically disdain for attempts to regulate the flow of disinformation and hate speech, is also a motivating factor for his powerful backers in Silicon Valley. Tech executives and investors have amplified Mr. Kennedy’s anti-establishment message and celebrated his willingness to challenge liberal orthodoxies and scientific consensus — never mind that in doing so, he has often spread widely discredited claims about vaccines and other public health measures.
And, for many prospective voters drawn to Mr. Kennedy, anger about censorship is a natural outgrowth of a deep distrust of authority that accelerated during the coronavirus pandemic, particularly in response to the lockdowns that public officials called on to halt the virus’s spread.
It is the latter group that is most diverse. Some are libertarians, searching for a standard-bearer; others are disaffected Democrats; some are Republicans looking for an alternative to Mr. Trump. Mr. Kennedy’s audience in New Hampshire of at least 250 people included at least one person wearing a Trump 2020 hat.
A fund-raising email from his campaign on Tuesday said it had raised “less than $4 million” since he entered the race in April. Official figures will be released in July, along with numbers from his PACs, which have separately said they brought in several million dollars.
Mr. Kennedy’s recent public appearances have tended to be before conservative or libertarian audiences. Last week, he spoke about environmental stewardship at a sold-out dinner hosted by the Ethan Allen Institute, a free-market, right-of-center think tank in Burlington, Vt. This week, he had been scheduled to speak at an event hosted by Moms for Liberty, a conservative organization that has, among other things, pushed for the banning of books that discuss race, gender and sexuality, but later canceled that appearance, citing a scheduling conflict, according to The Philadelphia Inquirer.
Despite this rightward tilt, Mr. Kennedy has emerged as a persistent thorn in the side of Mr. Biden, posing not so much a serious threat to the president’s renomination as a high-profile reminder that many Democratic voters would prefer new blood.
Mr. Kennedy’s support among Democrats reached as high as 20 percent in polls in recent months, but a Quinnipiac University poll this month also found Mr. Kennedy’s standing among Republicans to be fairly high: 40 percent viewed him favorably, compared with 31 percent of independents and 25 percent of Democrats. In New Hampshire, a Saint Anselm College Survey Center poll put his Democratic support in June at 9 percent.
Mr. Kennedy’s longtime admirers are not surprised. Debra Sheldon, 48, a Democrat from New York State, campaigned for Barack Obama in 2008. But when she had a child, she said, Mr. Kennedy’s Children’s Health Defense — a nonprofit group he formed that has campaigned against vaccines — “really helped inform me, as a new mom, about what was good for my kid.”
Children’s Health Defense has been widely criticized for spreading disinformation about vaccines, included discredited claims linking them to autism.
Ms. Sheldon is now a volunteer for Mr. Kennedy’s campaign, and was in New Hampshire selling his books and other materials about autism at the libertarian retreat, the Porcupine Freedom Festival. She described her mission in almost spiritual terms: “We are here to protect the soul of America.”
Some of Mr. Kennedy’s newer supporters said they were drawn to what they saw as his message of unity and fairness, an almost nostalgic perspective he often anchors in stories of his childhood in one of America’s most famous political families. But others described feeling “awakened” during the pandemic by questions Mr. Kennedy posed about vaccines, masks and school lockdowns, issues they felt were ignored — or, worse, stifled — by the mainstream media.
“All of those people watched over many years where Bobby was censored in every mainstream venue,” said Tony Lyons, whose company, Skyhorse Publishing, has picked up authors deemed unsavory or risky by other presses, including the filmmaker Woody Allen, the former Trump lawyer Michael Cohen, and Mr. Kennedy. Mr. Lyons is a co-chair of a PAC supporting Mr. Kennedy.
“Every TV show, venue — they just wouldn’t let him on to talk about his views on what Big Pharma companies were doing to the American public,” Mr. Lyons said. “He then kind of became a hero of the freedom of speech people,” a group that includes many political identities, he said.
Mr. Kennedy was kicked off social media platforms during the pandemic on the grounds that he had spread debunked claims about the virus. Instagram lifted its suspension in June, citing his presidential candidacy, after Mr. Kennedy complained about the suspension on Twitter. The complaint prompted Elon Musk — who calls himself a free speech absolutist — to invite him to a discussion on Twitter Spaces.
Mr. Kennedy has embraced cryptocurrency, as well: He spoke at a major Bitcoin conference in Miami last month, and his campaign is accepting Bitcoin donations.
He has also embraced podcasts, and recently recorded a more than three-hour-long appearance with Joe Rogan, whose immensely popular show reaches 11 million listeners per episode. The show, which has been criticized for spreading misinformation, largely caters to young men, and many of his listeners fall on the center-right of the political spectrum.
On the show, Mr. Kennedy described the modern Democratic Party as the “party of censorship.”
Jason Calacanis, a co-host of a popular podcast on which Mr. Kennedy appeared in May, said in response to questions about Mr. Kennedy’s appeal that his willingness to talk for hours on a podcast stood in contrast to Mr. Biden, who has held few news conferences.
“In the age of podcasting, Americans want someone sharp and willing to engage in vibrant debates,” Mr. Calacanis said. “Trump won in 2016 because of social media, and the next president will win because of podcasts.”
Mr. Kennedy and his PAC are drawing significant support from the tech world, including Jack Dorsey, the founder of Twitter who endorsed Mr. Kennedy, and David Sacks, a venture capitalist who has raised money for Republicans and Democrats alike.
Mark Gorton, a New York City trader who created the file-sharing service LimeWire, helped create and fund a PAC supporting Mr. Kennedy. The PAC, American Values 2024, has taken in at least $5.7 million, its leadership says — official numbers will be released next month.
Mr. Gorton said the pandemic “unlocked all this energy” among a “very marginalized group” of people pushing back against public health protocols who found themselves ostracized or “de-platformed” on social media. In Mr. Kennedy, they saw a hero.
Bill Barger, a 31-year-old from Manchester, N.H., who attended Mr. Kennedy’s speech Thursday, said he was “definitely interested” in Mr. Kennedy. But he wasn’t yet sold on Mr. Kennedy’s commitment to free speech.
He said he would like to see Mr. Kennedy debate Mr. Trump, whom he described as “funny as hell.”
On a radio show Monday, Mr. Trump hailed Mr. Kennedy’s poll numbers, calling him a “very smart guy.”
The two candidates share common fixations. During his speech in New Hampshire, Mr. Kennedy repeatedly invoked The New York Times as an example of corrupt media.
“The New York Times, which is in this room today,” he said, as an audience member pointed down at the Times reporter’s seat, prompting a chorus of boos so angry, Mr. Kennedy’s campaign manager — the former Democratic presidential candidate Dennis Kucinich — told the audience member to stop it.
Mr. Kennedy smiled for a few moments, then walked back across the stage. “I’m not saying the reporter who is here. She’s a very sweet person, by all accounts.”
Ruth Igielnik contributed reporting.