US presidential candidate Robert F Kennedy Jr has unveiled Silicon Valley lawyer and philanthropist Nicole Shanahan as his running mate. Shanahan, 38, the ex-wife of Google co-founder Sergey Brin, has never before run for political office. Kennedy, an environmental lawyer, anti-vaccine activist and scion of America's most famous political dynasty, is running as an independent. Naming a VP pick is a prerequisite to be on the ballot in a number of states. The Kennedy campaign has ruffled Democrats, who are concerned about its spoiler potential on President Joe Biden's re-election chances. The Democratic National Committee has recently stepped up attacks on Kennedy, arguing that his longshot third-party bid will only end up helping to elect the Republican candidate, Donald Trump. Shanahan has previously been a longtime Democratic donor and has already donated to Kennedy's campaign. She was unveiled on Tuesday by Kennedy at a rally in Oakland, California. He described her as someone with a deep inside knowledge of Big Tech, which he depicted as a threat to democracy. Kennedy told the crowd he picked a younger running mate partly because he wants her to be a champion for millennial and Gen-Z Americans who he said have lost hope for their future and no longer believe the political establishment has their best interests at heart. Kennedy was introduced at the event by his wife, Cheryl Hines, the star of HBO comedy Curb Your Enthusiasm. Kennedy, 70, previously challenged Biden for the Democratic party's nomination, before launching an independent bid last October. Naming Shanahan as his vice-presidential nominee will help his campaign clear the way for ballot access in many US states and Washington DC. His campaign has to navigate a wide variety of state rules to get his name on the ballot. On Monday, Kennedy threatened legal action against Nevada after state officials suggested signatures his campaign has gathered to qualify for the ballot there could be invalid, as he had no confirmed running mate at the time they were filed. So far, Mr Kennedy is only confirmed to be on the ballot in Utah. Shanahan's humble origins will serve as a contrast to Kennedy and his famous political family. The daughter of a Chinese immigrant mother and a white father, she grew up in Oakland and was raised on food stamps, a federal subsidy that helps low-income families buy groceries. She's previously recalled her childhood as being filled with fear and instability because of her dad's schizophrenia and bipolar disorder. Shanahan has supported criminal justice reform, affordable housing and efforts to fight climate change and to increase access to mental health treatment. In February, Shanahan acknowledged partially funding a Super Bowl ad released by Kennedy's campaign. The ad was a remake of a 1960 one that was part of the White House campaign run by his uncle, President John F Kennedy. The Super Bowl ad drew disapproval, including from members of RFK Jr's family, who criticized his vaccine skepticism. The BBC spoke with half a dozen of Shanahan's former and current colleagues before Tuesday's announcement. They described her as a compassionate leader and a champion of social causes. While most did not realize she was considering a political career, they were surprised but not shocked to see her name floated as Kennedy's vice-presidential nominee. "She's motivated by trying to change things for the better and having an impact on social benefits," said Roland Vogl, executive director of Stanford University's Center for Legal Informatics, where Shanahan has been a fellow. They said her political inexperience and age should not count against her. "Don't undersell someone who comes from outside a system to change the system," Bruce Cahan, a professional colleague, said. He said voters should be open to leaders who want to break into politics. "What if we can give them a chance to do what they want to do, and they've been responsible people, and they're really smart and they have networks that they use to bring new solutions into politics," he said. "I think it would show a younger group of leaders that politics is not a toxic profession, and doesn't have to be." Kennedy's campaign previously floated other names on the running mate shortlist, including American football star Aaron Rodgers, former Minnesota Governor Jesse Ventura, and former Democratic presidential candidates Andrew Yang and Tulsi Gabbard. Kennedy has insisted he is unfazed by the political uphill battle he faces. The last president to win without the backing of a major party was the first ever US president, George Washington. According to a January YouGov poll, just 1% of US voters would cast a ballot for Kennedy in an election that featured Biden and Trump. — BBC