Robert F. Kennedy Jr., environmental lawyer and anti-vaccine activist, is running for president in 2024 as a Democrat. The paperwork was filed with the Federal Election Commission this week. The campaign sent out a press release Thursday that the formal announcement would be held at Boston on April 19.

Mr. Kennedy is a nephew of President John F. Kennedy and the eldest son of a slain presidential candidate, Robert F. Kennedy. At a speech in New Hampshire last month, Mr. Kennedy told the Sun that running for office is “part of the DNA” of his family.  

The 69-year-old candidate’s campaign for the Democratic nomination is a long shot by any reckoning. President Biden has said he is planning to run, though he has yet to announce formally. Self-help author Marianne Williamson is the only other declared candidate in the race.

Mr. Kennedy’s campaign press release makes note of the uphill battle, drawing parallels to his father, “who in 1969 mounted a major campaign in a tumultuous primary that dislodged incumbent Democratic President Lyndon Johnson.”

Mr. Kennedy first made a name for himself as an environmental lawyer, working with groups like Riverkeeper, an organization that was instrumental in cleaning up the Hudson River in New York. His environmental activism, like protesting the Keystone XL pipeline or litigating against factory farms, aligns him with the Democratic Party base — but for his views on vaccines.

For the last nearly two decades, Mr. Kennedy has turned his focus to vaccines and what he claims is a link between them and childhood diseases like autism. This work prompted three of his family members in 2019 to pen an op-ed in Politico, titled, “RFK Jr. Is Our Brother and Uncle. He’s Tragically Wrong About Vaccines.”

In a speech in New Hampshire last month, though, Mr. Kennedy didn’t shy away from repeating his vaccine-harm claims. Since the start of Covid, Mr. Kennedy’s anti-vaccine views have gained more traction, and also condemnation, becoming something of a political dividing line.

By and large, Democrats embraced Covid vaccines and even mandates, while skeptics were more likely to be Republican or libertarian. This could pose problems for Mr. Kennedy as he vies for support within the Democratic Party. 

The Team Kennedy campaign press release makes no mention of Mr. Kennedy’s role in the vaccine resistance movement or the books he has written on the subject. His opponents, though, are sure to make this a central focus of their attacks.

After news broke that Mr. Kennedy is running, a CBS journalist, Robert Costa, tweeted, “Per several people familiar, Steve Bannon had been encouraging this for months and believes RFK Jr. could be both a useful chaos agent in the 2024 race and a big name who could help stoke anti-vax sentiment around the country.”

A photograph of Mr. Kennedy with a Republican operative, Roger Stone, and President Trump’s national security advisor, Michael Flynn, is being shared online. 

Mr. Kennedy is getting support from some libertarians. The director of the Ron Paul Institute, Daniel McAdams, tweeted a picture of himself with Mr. Kennedy, with the tagline, “Hanging out with my president.” A libertarian author, Jeffrey Tucker, of the Brownstone Institute, has also expressed support for Mr. Kennedy.  

A former libertarian Republican presidential candidate, Ron Paul, said, “He’s not libertarian, but on the issues — if he’s very libertarian on civil liberties and on the war issue — that’s pretty darn good.” 

Mr. Kennedy’s chances of winning the Democratic nomination are slim at best. Yet, if Mr. Biden is not on the ballot in New Hampshire, because the state is bucking the Democratic National Committee’s new nominating calendar by holding its primary first, then Mr. Kennedy could win the state’s primary — so long as no one else gets in the race.

Nearly 40 percent of Granite Staters are undeclared in party affiliation, which means they can vote in either party’s primary. There is a large libertarian population for such a small state. “I think he’d be popular among health freedom advocates and anti-mandate libertarians … I would vote for RFK,”  the chairwoman of the Free State Project, Carla Gericke, part of a movement to make New Hampshire a libertarian homeland, tells the Sun. “Doesn’t hurt that he’s a Kennedy.”