Sergey Brin confronted Gavin Newsom at a treehouse party — then launched a political war

In a treehouse nestled in redwoods north of San Francisco, California Governor Gavin Newsom stood cold and hungry as Sergey Brin, the world’s fourth-richest man, and his wellness-influencer girlfriend told him they were leaving the state.

It was late in the evening at a Christmas party hosted by crypto titan Chris Larsen — featuring singer Janelle Monáe and a towering abominable snowman with glowing red eyes — when Brin and his partner, Gerelyn Gilbert-Soto, confronted Newsom about a new proposal to tax billionaires in California, according to people who’ve spoken with the governor. Such a levy could hit Brin’s stake in Alphabet Inc. and his $272.6 billion fortune.

Newsom, who opposes the wealth tax, was still telling people about the lengthy exchange at the party months later, complaining of a lingering cold the pair had given him, according to the people, who asked not to be named discussing private conversations with the governor. 

Brin, meanwhile, followed through. He left the state, bought a lakeside mansion in Nevada, and started bankrolling a billionaire political uprising in California. 

Newsom through a spokesperson declined to comment on the interaction. “The governor has been very clear with everyone, no matter who they are, that this effort will do serious damage to the state, including for public safety workers and schools, at the expense of one special interest group,” Izzy Gardon, a spokesperson, said. A representative...