Jonnie-Mae Smith, a 45-year-old architectural engineer in Tampa, sits squarely in the mainstream when it comes to legalizing marijuana. She's not keen on recreational pot but would allow medical use.

It's personal.

"I have a friend up North, a nurse, who has third-stage breast cancer,'' Smith said. "She tried morphine, and all it does is constipate her. She has no appetite. The side effects of the opiates are so much worse. With marijuana, she functions. She goes to work and raises her kids.''

Such anecdotes are increasingly common as medical marijuana spreads east from its origins in cabernet-growing California, tree-hugging Oregon and latte-sipping Washington. All 20 medical marijuana states have experienced abuses, but they also have created a cadre of users with true medical needs that is swaying public opinion.

A Tampa Bay Times, Bay News 9 and AM 820 News Tampa Bay poll this month found that more than two-thirds of Tampa Bay residents favor legalizing medical marijuana. Only about one in four people opposes the idea.

This robust support mirrors that found in two Florida-wide polls taken earlier this year and helps a group pushing for a vote next November on legalizing medical pot. To become a constitutional amendment, the proposal requires a 60 percent majority to pass.

"The poll again demonstrates the broad support for a compassionate medical marijuana policy,'' said Ben Pollara, campaign manager for attorney John Morgan's United for Care campaign. "If given the chance, Floridians will overwhelmingly support a medical marijuana law.''

Calvina Fay, who runs an antidrug organization in St. Petersburg, attributes the poll results to insufficient information.

"When people are educated on these 'medicine by popular vote' initiatives, their opinions swing in the other direction," said Fay, executive director of Save Our Society from Drugs. "But regardless of whether one believes that street pot is medicine, when people examine the proposed amendment's language closely, they reject it because it is fraught with so many loopholes and opportunities for abuse that would be very bad for Florida."

By law, United for Care needs 683,149 valid petition signatures by Feb. 1 to get the proposal on the ballot. As a practical matter, though, the group acknowledges that it probably needs more than 900,000 signatures by early January. Election officials have 30 days to validate the signatures, and during the process many typically are thrown out. That's because signers move and fail to update their registration information, or signatures don't match, or people sign more than one petition.

As of Tuesday, United for Care had collected close to 800,000 signatures, including about 100,000 over the previous seven days, Pollara said.

The proposed amendment would set up state regulated dispensaries, prohibit home cultivation and require users to secure a doctor's approval.

That squares with strong sentiment that purely recreational use should remain illegal. About 60 percent of poll respondents opposed full legalization, with only 31 percent in favor.

Dylan Coderre, 22, of Pinellas Park reflects this split, favoring medical marijuana but opposing full legalization.

"People use pot as a reason to cope with life, and smoking makes you not want to do anything all day,'' said Coderre. "Your life will pass you by.'

Though various polls show support for medical marijuana, the percentages vary according to how the question is framed.

A November poll by Quinnipiac University mentioned "allowing" adult use with a doctor's prescription.

Florida's proposed amendment would not limit use to adults. Doctors would have to approve medical use but could not "prescribe'' pot because it is not a prescription drug.

The Quinnipiac poll found 82 percent of Floridians supporting medical marijuana. The Tampa Bay Times/Bay News 9/AM 820 poll asked about "legalizing'' medical marijuana — without mentioning the age of users or physician involvement — and found 68 percent in favor.

The telephone poll of 625 registered voters was taken Dec. 12-17 and has a 3.9 percentage point overall margin of error.

Support for medical marijuana cut across age and gender lines with one generational difference: Voters younger than 55 favored it 74 to 17 percent, while those 55-plus favored it 62 to 32 percent.

David Christein, 65, of St. Petersburg opposes medical pot because he thinks it can be addictive and be a gateway to drugs such as cocaine and heroin.

"There is enough marijuana use already,'' Christein said. "This would just give people another way to get it. And I don't have a lot of faith in the government to regulate things either.''

Jeffrey Harper, 70, of St. Petersburg supports full legalization. His younger brother suffered several severe back injuries, Harper said. Marijuana could ease the pain without the side effects of prescription painkillers that are chemical cousins to heroin, he said.

"It's kind of insane not to let people get relief while oxycodone and other stuff is legal.''

Prisons are full of people charged with possessing and selling pot on a small scale, Harper said. Why not legalize and tax pot, instead of spending money on incarceration?

As for his personal experience: "I used it just once, and it didn't do anything for me. And smoking makes me sneeze.''

Contact Stephen Nohlgren at nohlgren@tampabay.com.