The consultant who once warned that California’s richest poured millions into politics because they had something to gain is now helping billionaires fight a tax on their fortunes.

Ned Wigglesworth, who decried the “billionaire boys’ club of politics” as a campaign finance reformer decades ago, is a key strategist behind Building a Better California, the political organization opposing Proposition 40, the November ballot measure that would impose a one-time 5% tax on Californians worth at least $1 billion.

The campaign has already pulled big Silicon Valley money—Google cofounder Sergey Brin alone contributed over $100 million to the group, with venture capitalist John Doerr and crypto billionaire Chris Larsen also putting money into committees fighting the tax. Building a Better California has also reserved $87 million worth of advertising ahead of the vote.

It’s unclear what led Wigglesworth from opposing the political influence of California’s wealthy to helping them defeat a tax targeting their wealth. The San Francisco Standard called him a “billionaire whisperer” while citing several interviews with anonymous colleagues of his who described him as a creature of Sacramento lobbying. His LinkedIn profile shows him at several communications firms: founding partner and CEO of Spectrum Campaigns for the past 10-plus years, and previously a partner at Redwood Pacific Public Affairs, Vice President at Goddard Claussen/West and Vice President at the California Medical Association. Presumably, Wigglesworth’s clients have migrated from less to more billionaire-friendly over time; he did not respond to Fortune‘s requests for comment.

But the arc of Wigglesworth’s career reflects a tension that has long percolated through California politics: the Golden State state has produced extraordinary concentrations of wealth and a political appetite for taxing it while relying on the wealthy people and companies behind that prosperity.

Gov. Gavin Newsom has been caught in this bind, both an opponent of the billionaire tax and yet an advocate for reducing inequality as it’s become a potent issue for Democrats. Newsom has proposed higher taxes on the ultrawealthy at the federal level and argued that California needs to “democratize our economy” amid the rhetoric of AI-related job loss.

As a campaign finance watchdog two decades before the billionaire tax proposition, Wigglesworth warned Californians about what happened when wealthy donors flooded politics with cash. “There’s some very wealthy and powerful special interests who have enough at stake to spend 150 million bucks ,to either defend their turf or improve their bottom line,” Wigglesworth said in 2005. “These people aren’t spending money out of some benevolent sense of improving societal good, improving the public good. This is about people fighting for their piece of the pie.”

“In other words,” Wigglesworth wrote in a 2007 Capitol Weekly column, “they give because they get.”

California’s wealth tax battle offers an especially vivid test of Wigglesworth’s (onetime) thesis. Prop. 40 would hit roughly 200 billionaires who lived in California as of Jan. 1 with a one-time levy equal to 5% of their wealth. Supporters say the measure could generate around $100 billion, with most of the proceeds earmarked for health care after federal Medicaid cuts.

But for the billionaires affected, the potential bills are enormous, with Brin reportedly owing $13 billion if the measure passes. He and fellow Google cofounder Larry Page moved out of California before the Jan. 1 cutoff and have since amassed roughly $225 million in Miami real estate.

The tax has also sparked public sparring over whether California risks driving away the people who pay an outsized chunk of its bills, with nearly half of the state’s personal income tax revenue coming from the top 1%. Gov. Gavin Newsom opposed the measure on those grounds. Venture capitalist Vinod Khosla said he has no plans to leave California, but has warned the state could permanently damage its tax base if wealthy residents flee.

The sums involved today dwarf even the spending Wigglesworth was warning about more than 20 years ago. California’s 15 richest billionaires had poured more than $336 million into state and federal elections this year, with Brin, Marc Andreessen, Ben Horowitz and Larsen accounting for $331 million of the total.