California voters are set to decide on Tuesday, November 3, whether to impose a one-time 5% wealth tax on billionaires. The proposal was backed by a health-care union and developed by economists Gabriel Zucman and Emmanuel Saez.

The measure was once presented by supporters as a vote with potential consequences beyond California. In early October, Vermont Senator Bernie Sanders told an audience in Los Angeles that “the whole country is watching.”

But the proposal has lost ground in recent polling. A survey published October 29 by the University of California, Berkeley’s Institute of Governmental Studies found that 42% of respondents planned to vote in favor, while 50% intended to oppose it and 8% were undecided.

That marks a reversal from earlier surveys. In mid-September, 45% supported the measure and 42% opposed it; in early August, the figures were 48% and 41%. In March, support stood at 52%, compared with 33% opposed.

The campaign has faced a major counteroffensive from Google co-founder Sergey Brin and others, who have warned that the tax could prompt billionaires to relocate to states such as Texas or Florida.

Sources: Le Monde Économie.