Robert F. Kennedy Jr., nephew of President John F. Kennedy and son of former U.S. Attorney General Robert F. Kennedy, is running for president as a Democrat, according to a statement of candidacy filed with the Federal Election Commission on Wednesday.

Kennedy, an outspoken anti-vaccine activist and the chair of the anti-vaccine nonprofit group Children’s Health Defense, is the second Democrat to officially enter the 2024 race. Self-help author Marianne Williamson launched her second White House bid in March.

Both Kennedy’s and Williamson’s bids are seen as long-shots in a Democratic primary that will likely pit them against President Joe Biden. Though Biden has yet to officially enter the race, he has repeatedly said he plans to run for reelection.