Florida was supposed to change the way the South thinks about medical marijuana. In late July, a full 88 percent of the state supported legalizing medical cannabis, and in early October 67 percent supported Amendment 2 specifically.* Instead, that wide margin has all but disappeared, and rather than join the 23 other states with similar laws on the books, the amendment appears to be bleeding support by the hour.

A private trend poll commissioned by an out-of-state company has shown a clear downward tick in the final week before Election Day, and a Tampa Bay Times “insiders poll” of state political experts has more than 80 percent expecting a loss. It’s still too close to call, but if the initiative fails on Tuesday, Florida will make a different sort of history: It will be the largest state to ever reject legal medical marijuana by popular vote.

“It seemed like we had the prime opportunity for Florida to do something novel and different,” said state Rep. Katie Edwards, a Democrat from Broward County who co-sponsored a successful, but more limited, compassion law for severely sick patients earlier this year. “So what the hell happened?”

Opinions and frustrations over the amendment’s nosedive are not in short supply, and blame is already being widely ascribed. But in conversations with those involved, one common culprit is revealed: dysfunctional partisanship.

United for Care, the group promoting the amendment, is a strictly Democratic affair, and the campaign’s financial burden has been carried almost entirely by one man—Orlando trial lawyer John Morgan, a household name in Florida for his ubiquitous television commercials.

Morgan has made compassion a hallmark of his “Yes on 2” campaign, and he points to his brother, who was paralyzed from the chest down at 18 years old and suffers from chronic pain and spasms, as an example of a patient in need. Nevertheless, the campaign that Morgan has bankrolled with roughly $4 million of his own money has become inseparable from party politics and Charlie Crist, the Democratic candidate for governor who happens to work at Morgan’s Orlando law firm.

Since it launched, Florida Republicans have suspected that Morgan’s campaign is actually an effort to pump voter turnout in an off-year election and help Crist eke out a win against incumbent Gov. Rick Scott. Morgan denies he’s playing politics, telling the Tampa Tribune that he’s “not as smart or devious as they think I am.” And yet, when he hired a campaign manager, he picked Ben Pollara, an operative who describes himself as “one of the premier Democratic fundraisers in Florida.” Pollara served on President Obama’s 2012 National Finance Committee, was the state finance director for Hillary Clinton’s 2008 presidential bid, and has represented Democrats including Sen. Bill Nelson, Sen. Kirsten Gillibrand, and Rep. Debbie Wasserman Schultz.

“It has not been a bipartisan campaign,” says Pollara. “The opposition has been run entirely by Republican operatives and funded by Republican mega-donors.”

Indeed, Pollara is now in the unenviable position of running a campaign against Sheldon Adelson, the Las Vegas business tycoon who in 2012 spent more money than any single person has ever spent on an American election. On May 29, Adelson sent $2.5 million to the Drug Free Florida Committee and to date has contributed $5 million, or 85 percent of the total budget against the measure. Some speculate that Adelson’s interest is personal; the Adelsons lost a son to a drug overdose in 2005. Others think he is simply trying to turn out conservative voters to help Gov. Scott. Regardless, according to Stephen Gutwillig at the Drug Policy Alliance, Adelson has made this the most well-funded drug policy campaign, ever.

“It’s very unusual for an issue with such widespread mainstream support,” Gutwillig said, citing the surge in national approval of medical cannabis.

The “No on 2” campaign has spent most of its windfall on a deluge of television ads that started running statewide at the end of September, about a month after August polling detected a falloff in support. The ads are savvy—dressing up tiny decontextualized bits of fact with a high gloss of exaggeration and fear-mongering. “It’s hard enough to reach Florida’s supermajority without an onslaught of misleading ads,” says Gutwillig.

What makes the entire struggle over Amendment 2 harder to understand is that there was strong bipartisan support for medicinal marijuana in the state even a few months ago. In March, two young state representatives, Republican Matt Gaetz, 32, and Democrat, Katie Edwards, 33, teamed up to sponsor the Compassionate Medical Cannabis Act. The law, which Gaetz characterized as “a bipartisan effort from start to finish,” permits certain high-CBD and low-THC strains to be prescribed for children and adults with epilepsy, cancer, and other chronic conditions. The bill sailed through the Republican-controlled legislature.

“I do believe that cannabis is medicine,” said Gaetz, a panhandle conservative. “I support a more modern cannabis policy in my state, and I am the chairman of the Criminal Justice Committee.” But he never supported the Amendment 2 ballot initiative. “Mostly because I wasn’t really involved in the creation of Amendment 2.”

Pollara never reached out to Gaetz, the key pro-cannabis Republican in the state. “We have not really been pursuing endorsements from elected officials,” Pollara explained. “Most people have no idea who their state representative and state senator are, much less care what they think about medical marijuana.”

Even Democratic lawmakers don’t agree with that analysis. “If you’re going to pass a constitutional amendment in Florida, you have to have bipartisan support and bipartisan outreach,” Edwards said.

Early on, medical marijuana in Florida, and Amendment 2 specifically, had an ideologically diverse base of support. The movement even included Roger Stone, the veteran political strategist who has been working as a libertarian consultant since he formally left the GOP after more than 30 years as a party insider. “All of my activism on behalf of medicinal marijuana was altruistic. I’m a libertarian, and it’s what I believe,” said Stone. But as he watched the campaign over Amendment 2 turn into a political knife fight, something Stone knows all too well, he walked away.

Nearly $10 million has been spent on Amendment 2 in Florida, and if it loses on Tuesday, it will be a rare—and costly—loss for the forces pushing to liberalize medical marijuana around the country. Referendums on full and regulated legalization will also be decided on Tuesday in Alaska, Oregon, and the District of Columbia, all of which are trending more favorably than Florida’s Amendment 2.

“The campaign got embroiled in gubernatorial politics, and it’s a tragedy,” Stone said. “The reason it’s a tragedy is because the people who really need help will suffer. They needed this to be truly bipartisan, and it wasn’t.”

*Correction, Nov. 3, 2014: This article originally misstated the percentage of Floridians who supported Amendment 2. Eight-eight percent of the state supported legalizing medical cannabis as of July, and in early October 67 percent supported Amendment 2 specifically. (Return.)