California Democrats defy Newsom, back billionaire tax on the November ballot.

California Gov. Gavin Newsom, a Democrat, opposes the billionaire tax on voters’ ballots this November. So does Xavier Becerra, the Democratic gubernatorial candidate widely favored to succeed him.

That didn’t stop the state Democratic Party from narrowly endorsing it.

Proposition 40 would generate an estimated $100 billion by levying a one-time 5% tax on the state’s more than 200 billionaires. The bulk of the proceeds would go toward backfilling federal cuts to the state’s expansive low-income health program, Medi-Cal.

The idea has sparked controversy ever since a health care workers’ union proposed it late last year, prompting tech billionaires like Google co-founder Sergey Brin to move his business holdings out-of-state and pump millions of dollars into political committees to kill it.

“This is not a kumbaya measure.”

After a contentious endorsement vote among the California Democratic Party’s top statewide activists and officials over the weekend, it’s shaping up to be the latest intra-Democratic fight exposing deep party divisions over November’s ballot.

“This is not a kumbaya measure,” said Nancy Tung, chair of the San Francisco Democratic Party, who voted against the endorsement. “There are very serious disagreements among Democrats and Democratic institutions that are opposed to each other over the measure.”

After the vote, Dave Regan, president of SEIU United Healthcare Workers West, released a statement saying the “endorsement puts to rest the idea that California Democrats are not united by the billionaire tax – they are.”

But undecided liberal voters may be confused to see the party pitted against some of its highest-profile leaders. In addition to Newsom and Becerra, doctors’ and primary care providers’ associations oppose the billionaire tax, along with a variety of Democratic-aligned political powerhouses like Planned Parenthood. Several labor unions are opposed. The powerful, 750,000-member SEIU California last week chose not to take a position.

Opponents worry the tax would drive the wealthy out of the state, depriving California of both income tax revenue and spending. California’s progressive income tax system means its revenues are particularly dependent on the fortunes of the wealthy. Some interest groups are opposed, too, because the measure primarily dedicates its revenues toward a single state program: health care.

The No campaign downplayed the party’s endorsement, pointing to the party’s 2024 opposition to Prop. 36, a crime measure which nonetheless passed overwhelmingly, and its support for Prop. 32, a minimum wage hike which failed.

Newsom, Becerra, California Teachers Association, California Professional Firefighters, Planned Parenthood and others are against Prop. 40 “because it’s bad for our budget, bad for our economy, and bad for our future,” the campaign said in a statement.

MAYA C. MILLER and JEANNE KUANG cover politics at CalMatters, where this story first appeared.