BOSTON — Anti-vaccine activist Robert F. Kennedy Jr. launched his long-shot bid to challenge President Joe Biden for the Democratic nomination next year.

Kennedy, a member of one of the country’s most famous political families who has in recent years been linked to some far-right figures, kicked off his campaign Wednesday in Boston and likened his campaign to the American Revolution.

“My mission over the next 18 months of this campaign and throughout my presidency will be to end the corrupt merger of state and corporate power that is threatening now to impose a new kind of corporate feudalism,” Kennedy said.

Self-help author Marianne Williamson also is running for the Democratic nomination.

Biden has not formally announced a campaign, but he is expected to have much of the Democratic establishment behind him.

Kennedy, a nephew of slain President John F. Kennedy and the son of his slain brother Robert F. Kennedy, repeatedly referenced both during his speech Wednesday.

Kennedy Jr. was once known most as an environmental lawyer who worked on issues such as clean water. But over the past nearly two decades, he has become one of the leading voices of the anti-vaccine movement. His work has been described by relatives and public health experts as misleading and dangerous.

His efforts intensified after the pandemic and development of the COVID-19 vaccine, and an AP investigation in 2021 showed he had linked up with anti-democratic figures. He has appeared at events pushing the lie that the 2020 presidential election was stolen and with people who cheered or downplayed the insurrection at the U.S. Capitol on Jan. 6, 2021.