INDEPENDENT US presidential candidate Robert F. Kennedy Jr announced wealthy Silicon Valley lawyer and political newcomer Nicole Shanahan as his running mate on 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 per cent 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.

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.

“Technology has been a life-long passion for my future vice-president,” Kennedy, 70, told around 500 supporters at the announcement in Oakland, California.

“It’s important because I also wanted a vice-president who shares my indignation about the participation of big tech as a partner in the censorship and their surveillance, and the information warfare that our government is currently waging against the American people.”

GET BT IN YOUR INBOX DAILY

Start and end each day with the latest news stories and analyses delivered straight to your inbox.

Sign UpVIEW ALL

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

She told The New York Times she helped make an attention-grabbing Super Bowl ad supporting Kennedy in February, and gave US$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 whom she said was “plagued by substance abuse” and struggled to keep a job.

‘Purpose of privilege’

“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 back I want to bring that back to politics too. That is the purpose of privilege.”

Shanhan 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.”

Shanahan, who has an autistic daughter, told The New York Times in February that concerns about children’s health, including vaccines, had motivated her to support Kennedy.

She said she was “not an anti-vaxxer” but added: “I do think that the increase of vaccine-related injuries is very alarming, and I do think we need to understand the screening mechanisms.”

Kennedy was the head of anti-vaccine organisation Children’s Health Defence, before stepping back to run for president.

He has leaned heavily on the iconic status of his uncle - and his father, JFK’s younger brother and attorney general Robert F. Kennedy - on the campaign trail and spoke at length about his father’s work targeting poverty.

But four of his siblings have condemned his campaign, saying that he “does not share the same values, vision or judgment” as their father.

Trump’s victory margin over Hillary Clinton in several key swing states in 2016 was smaller than third party candidate Jill Stein’s vote total.

The Biden campaign and the Democratic National Committee have allocated staff and consultants to specifically to the mission of attacking Kennedy. AFP