With a cadre of like-minded, wealthy donors, Mr. Soros is dominating the pro-legalization side of the marijuana debate by funding grass-roots initiatives that begin in New York City and end up affecting local politics elsewhere.

 

Through a network of nonprofit groups, Mr. Soros has spent at least $80 million on the legalization effort since 1994, when he diverted a portion of his foundation’s funds to organizations exploring alternative drug policies, according to tax filings.

His spending has been supplemented by Peter B. Lewis, the late chairman of Progressive Insurance Co. and an unabashed pot smoker who channeled more than $40 million to influence local debates, according to the National Organization for the Reform of Marijuana Laws. The two billionaires’ funding has been unmatched by anyone on the other side of the debate.