The billionaire financier has pledged $12 million to oppose the measure, according to spokesman Zia Ahmed. The constitutional amendment will be decided by voters in November and needs at least 60% approval to pass.

In an opinion article published Friday in the Miami Herald, Griffin argued that the proposed amendment would create a monopoly for large marijuana dispensaries and allow cannabis use in public and private areas across Florida.

In addition to his anti-legalization efforts, Griffin is also contributing $8 million to committes funding Republican candidates running for the Florida legislature, Ahmed said.

The founder of Citadel and Citadel Securities, who relocated from Chicago to Miami in 2022, has been wielding his $42 billion fortune to influence Florida’s political landscape and to fund philanthropic causes.

Earlier this year, he condemned a proposed casino expansion in South Florida, likening it to “dumping toxic waste into the Everglades.” Legislators buried it soon after. Last year, he played a key role in watering down a proposal restricting real estate purchases by Chinese nationals, before it was enacted. In June, he gave $500,000 to back the reelection campaign of Miami-Dade County’s Democratic mayor, Daniella Levine Cava. 

“I have lived the nightmare of misguided politicians in other states whose policies are destroying jobs, fostering crime, ravaging schools, and damaging communities,” Griffin said in a statement to Bloomberg News. “I am committed to supporting policies and principles that will further elevate Florida as the greatest place to live, work, and raise a family in America.”

In the opinion piece, Griffin argued that legalizing recreational marijuana will primarily benefit special interests, while leading to more “dangerous roads, a higher risk of addiction among our youth, and an increase in crime.”

So far, more money has gone into Florida’s referendum on legalizing weed, known as Amendment 3, than any other ballot measure in the US this year, according to OpenSecrets, a non-partisan campaign finance group.

Safe & Smart, a political committee in support of legalization, has raised $66.7 million, according to Florida finance disclosures. 

A recent University of North Florida poll found 64% of Floridians support legalization. However, Republican Governor Ron DeSantis, who has received political contributions from Griffin, has voiced strong opposition, warning that legalization would lead to an increase in marijuana use similar to that in cities like San Francisco and Chicago.

“We cannot have every town smelling like marijuana. We cannot have every hotel, theme parks smelling,” DeSantis said in June. “It’s going to be everywhere.”