Some food and agriculture experts predict food companies would remove genetically modified ingredients rather than label them just for California - a move that would hit the multi-billion genetically modified seed business, where Monsanto and DuPont are market leaders.
Monsanto, the largest backer of the campaign with more than $8 million in funding, and DuPont say Proposition 37 would mislead consumers. PepsiCo referred reporters to the "No on 37" campaign.
TARGETING FLAWS IN INITIATIVE
Consumer advocates say the "No on 37" campaign has employed many of the same tactics the tobacco industry used this summer in California in a $47 million campaign that defeated Proposition 29, which would have raised cigarette taxes by $1 per pack to fund cancer research and other health efforts.
Opponents of the tobacco tax overcame early support approaching 70 percent by flooding airwaves with ads, including one featuring a doctor in a white coat warning that tobacco tax proceeds would not be spent on cancer treatment and could be shipped out of state. Outgunned supporters said those claims were false.
The food and tobacco industry campaigns both employed messages that weren't "arguing with the premise of the initiatives, but rather making picky criticisms of the details of the initiatives," said anti-smoking activist Stanton Glantz, a professor and researcher at the University of California-San Francisco.
"No on 37" spokeswoman Kathy Fairbanks rejects the notion of copycat tactics and said the similarities between the two campaigns are limited to pointing out flaws in the initiatives and spending significant money on ads.
Backers of Proposition 37, including thousands of individual donors, organic food companies and natural health news provider Joseph Mercola, have been outspent roughly six to one, according to campaign reports filed with the California Secretary of State. In their final push, they are trying to trumpet cases where they say opponents have used misinformation to sway the public.
MISSTEPS ON BOTH SIDES
Both sides have made missteps.
Supporters of Proposition 37 got a boost when the Academy of Nutrition and Dietetics said "No on 37" inaccurately stated in the California official voter information guide that the academy had concluded that GMOs were safe.
"We are concerned that California's voters are being misled to believe the nation's largest organization of food and nutrition professionals is against Proposition 37, when in fact, the academy does not have a position on the issue," its president said in a statement in early October.