California Governor Gavin Newsom is facing a high-stakes political offensive from his own party’s progressive wing as supporters of a proposed billionaire tax launch a multi-state advertising campaign aimed at eroding his reputation in key presidential primary territories. The campaign, which includes television and digital ads, specifically targets Newsom’s opposition to Proposition 40, a California ballot measure that seeks to impose a 5% tax on the assets of billionaires.
The advertising blitz is strategically concentrated in states that play a pivotal role in the early stages of the presidential nominating process, including South Carolina, Nevada, New Mexico, Virginia, and New Hampshire. The timing is particularly notable given Newsom’s recent activities on the national stage, including a stumping tour for other candidates in New Hampshire earlier this month. While Newsom has not officially declared a 2028 presidential bid, he is widely regarded as a top-tier future contender for the Democratic nomination.
At the center of the dispute is Proposition 40, a measure designed to generate revenue to offset federal healthcare funding cuts that were approved by congressional Republicans and signed into law by former President Donald Trump last year. Proponents of the measure argue that the tax would save healthcare coverage for millions of residents. The 30-second ad being deployed in primary states frames Newsom’s opposition as a betrayal of his base.
In the ad, a narrator highlights the struggle of working families with healthcare costs and points to Proposition 40 as a solution championed by many California Democrats. The spot then shifts to a direct attack on Newsom, asking why the governor would “betray his own supporters by trying to sabotage the billionaire tax.” It suggests a financial motive, alleging that billionaires who oppose the measure have contributed millions of dollars to Newsom’s past political campaigns.
The advertisement identifies several prominent billionaires who have backed the governor’s political career, including Stewart Resnick, the owner of Fiji Water and Pom Wonderful; former Google executive Eric Schmidt; venture capitalist Michael Moritz; and cryptocurrency executive Chris Larsen. By naming these figures, the ad campaign seeks to link the governor’s policy positions to the interests of his wealthiest donors.
Newsom has defended his stance by arguing that wealth taxes are most effective when enacted at the national level rather than through a state-by-state approach. He has expressed concern that a localized tax could lead to an exodus of the state’s wealthiest residents, which could destabilize California’s budget, as the state is heavily dependent on income tax revenue from top earners.
The campaign against the governor is being funded by a coalition led by the Service Employees International Union (SEIU) United Healthcare Workers West, the original crafters of Proposition 40. Other major contributors include Saikat Chakrabarti, a climate advisor and former founding engineer at the financial technology company Stripe, and Ross Boucher, another early Stripe engineer.
The initial ad buy is valued in the six-figure range, though organizers indicate the budget could expand as the election nears. The battle over Proposition 40 has created a visible rift within the Democratic coalition. While Newsom remains a vocal opponent, the measure has secured endorsements from the California Democratic Party and Senator Bernie Sanders of Vermont. Recent polling suggests that voters in California remain closely divided on the proposal as they head toward the November election.
