san francisco   |   Billionaire financier George Soros has thrown his weight behind California’s marijuana legalization measure with a $1 million donation a week before the vote.

The contribution, reported Oct. 26 by the Sacramento Bee, is the single biggest donation from an individual other than Proposition 19’s main sponsor, Oakland medical marijuana entrepreneur Richard Lee.

George Soros

Soros, a Jewish high-profile liberal and philanthropist, has long backed drug law reform. He was one of the top financial backers of California’s first-in-the-nation measure legalizing medical marijuana in the state in 1996.

But Soros held off on openly endorsing Prop. 19 until writing an op-ed published Oct. 26 in the Wall Street Journal. In the piece, Soros said legalizing and taxing marijuana would save taxpayers the costs of incarceration and law enforcement while raising revenue for the state.

“Just as the process of repealing national alcohol prohibition began with individual states repealing their own prohibition laws, so individual states must now take the initiative with respect to repealing marijuana prohibition laws,” Soros wrote.

The $1 million donation came one day after the Yes on 19 campaign launched its first television ad. The opposition’s campaign also recently took to the airwaves for the first time with a radio ad sponsored by the California Chamber of Commerce, claiming the law would threaten workplace safety and harm the state’s economy.

Soros’ money went to a campaign committee overseen by the Drug Policy Alliance, a drug legalization advocacy group. Soros sits on the group’s board and is a major donor.

George Zimmer

The money will be spent on get-out-the-vote efforts, on-the-ground campaigning and television advertising, said Ethan Nadelmann, the alliance’s executive director and a longtime adviser to Soros on drug policy issues.

Soros has long supported medical marijuana and decriminalizing the drug for personal use but has been ambivalent about broader legalization, Nadelmann said. The 80-year-old investor finally decided to support Proposition 19 after seeing how the ballot measure had “elevated the discourse” around drug law reform, he said.

“For him, it’s not been about legalization per se, but about rolling back the drug war,” said Nadelmann.

Until this week, neither side in the ballot measure contest has seen a huge outpouring of cash, though supporters have significantly out-raised opponents. Supporters of the measure had raised about $3.8 million, including the Soros donation. The No campaign had raised about $300,000.

Other high-profile donations to Proposition 19 in recent days include $50,000 from Men’s Wearhouse chief executive George Zimmer — a Jewish, longtime Bay Area resident — and $70,000 from hedge fund president and Paypal co-founder Peter Thiel, according to campaign finance records.

Roger Salazar, spokesman for the No on Prop 19 campaign, called the big-ticket donations to the other side a sign of panic as polls show support for the measure dropping.

“We’ve always known that they would outspend us. In fact, they’ve outspent us from day one,” Salazar said. “It seems to us the more they’ve spent, the more they’ve gone down in the polls.”