George Soros, the multibillionaire investor who helped bankroll three initiatives to change drug laws in California, endorsed the marijuana legalization initiative Monday and plans to make a major financial contribution to the campaign.

Soros, who invested $3 million in the medical marijuana initiative and two other measures, made his announcement in an opinion piece published online by the Wall Street Journal. "Proposition 19 already is a winner no matter what happens on election day. The mere fact of its being on the ballot has elevated and legitimized public discourse about marijuana and marijuana policy in ways I could not have imagined a year ago," Soros wrote. The article is scheduled to appear in Tuesday’s print edition.

Soros, who runs a hedge fund and founded the Open Society Foundations, has not yet donated to the campaign. But Michael Vachon, an advisor to Soros, said that "he plans to make a significant contribution."

Related: L.A. Sheriff will enforce pot laws even if Prop. 19 passes.

The initiative was the brainchild of Richard Lee, an Oakland medical marijuana entrepreneur who has spent at least $1.5 million to draft the measure, collect signatures to qualify it for the ballot and pay for a campaign. The wealthy donors who have helped to pay for past efforts to change California’s drug laws had largely stayed out of the campaign until the last few weeks.

Peter B. Lewis, a retired insurance company executive, recently donated $209,005 to the campaign, and George Zimmer, the founder and CEO of Men’s Wearhouse, recently gave $50,000. Both businessmen

supported past initiatives to change the state’s drug laws.