Longtime environmental lawyer and anti-vaccine activist Robert F. Kennedy Jr. said Monday he will run for president as an independent and drop his Democratic primary bid, adding a wrinkle to a 2024 race heading toward a likely rematch between President Joe Biden and former President Donald Trump. Speaking on Monday in Philadelphia , Kennedy said he declared his independence from corporations, the media and the two major political parties. “But to do that, I must first declare my own independence, independence from the Democratic Party and from all other political parties,” Kennedy said. Kennedy, a member of one of the most famous Democratic families in politics, was running a long-shot primary bid and has better favorability ratings among Republicans than Democrats. It’s unclear whether GOP support would translate to a general election when Kennedy would also be running against Trump. Allies of both Biden and Trump have at times questioned whether Kennedy would be a spoiler against their candidate. Biden's allies so far have dismissed Kennedy’s primary campaign as unserious. Four of Kennedy's eight surviving siblings put out a joint statement denouncing his candidacy and saying his announcement saddened them. Hundreds of supporters gathered at Philadelphia's Independence Mall, an apt location for the launch. Campaign signs teased a potential new slogan: “Declare your independence.”