California’s Proposition 37 proposed to label cereals, sodas and other products containing genetically modified ingredients. Proponents said their effort was about empowering consumers who deserve to know what's in their food. Legal scholars said the right to know contained in Proposition 37 also came with the right to sue. Advocates relied on social media and a strong grass-roots campaign in hopes of making California the first state in the nation to require a “genetically-modified” statement on the labeling of various food products, from breakfast cereals to tofu.

Still, supporters were outshone by a well-organized "no" campaign that dispensed $46 million into defeating Proposition 37 and covered California with advertising.

The battle over Proposition 37 was an unusually high-profile fight because it pitted businesses against businesses. Big natural-food companies, celebrity chefs and several organic farmers were on one side, while a variety of traditional farmers and chemical, seed and processed-food companies were on the other.