OAKLAND: Independent US presidential candidate Robert F. Kennedy Jr. announced wealthy Silicon Valley lawyer and political newcomer Nicole Shanahan as his running mate Tuesday, as he pursues an anti-establishment campaign seen as an increasing threat to Democrat Joe Biden.

The nephew of John F. Kennedy and prominent vaccine skeptic is more popular than any independent candidate since Ross Perot in 1992, with average support of around 12 percent nationwide.

Democrats fear that nostalgia for their party's iconic political dynasty could make a significant dent in Biden's vote count as the president and his Republican predecessor Donald Trump vie for a second term in November.

Independent presidential candidate Robert F. Kennedy Jr. speaks during a campaign event to announce his pick for a running mate on March 26, 2024 in Oakland, California. PHOTO BY THOS ROBINSON / GETTY IMAGES NORTH AMERICA / GETTY IMAGES VIA AP

A tech entrepreneur and Democratic donor with no political experience, Shanahan was on a shortlist that included New York Jets quarterback Aaron Rodgers, former Minnesota governor Jesse Ventura and TV host Mike Rowe.

Kennedy, 70, told around 500 supporters in Oakland, California he wanted a vice president who would "speak for millennials and Gen Z — someone who cares about healing our children, protecting our environment, restoring our soils, and getting the chemicals out of our food, and who understands how technology will either enslave us or give us a path back to freedom and prosperity."

Shanahan, 38, founded a tech law firm in 2013 that uses AI to analyze patent portfolios.

She told The New York Times she helped make an attention-grabbing Super Bowl ad supporting Kennedy in February, and gave $4 million to a political group last month to air it.

The philanthropist gave a deeply personal speech about a difficult childhood with a father who she said was "plagued by substance abuse" and struggled to keep a job.

"As you probably know, I became very wealthy later on in life, but my roots in Oakland taught me many things I've never forgotten — that the purpose of wealth is to help those in need," she said.

"That's what it's for. And I want to bring that back to politics too. That is the purpose of privilege."

Shanahan was married to Google co-founder Sergey Brin for four years from 2018 and denied "senseless and cruel" media reports of an affair with tech billionaire Elon Musk that she blamed for the breakdown of her marriage.

She founded the Bia-Echo Foundation, which promotes "reproductive longevity and equality, criminal justice reform and a healthy and livable planet."