In more than 30 years in politics, Bobby Starr had never seen anything like it.

The Vermont state senator, a Democrat, represents a remote, rural district on the Canadian border. For the past couple of years, everywhere he went, everyone from villagers at their annual town meeting to children at a school assembly wanted to talk about genetically modified organisms in their food.

The people bringing it up weren’t outside agitators or stereotypical Vermont hippies. “They were just ordinary citizens,” Starr told me recently. “I’ve lived here all my life basically to this point, so I know them.” Though Starr, a farmer and former truck driver, had previously chaired the senate’s agriculture committee for more than a decade, he had no strong feelings one way or the other about the idea of requiring labeling of genetically modified, or GM, ingredients. He’d always looked out for farmers, and they were mostly against labeling. But it was clear what his constituents wanted. “I’ve always been pretty good at remembering who I represent,” he says.

So Starr became a supporter of a GMO-labeling bill in the Vermont legislature. He had plenty of company. When the legislature held public hearings on the labeling bill in 2012 and again this year, the chamber filled to overflowing with people who wanted to testify both times. Not a single member of the public spoke against the legislation. The final vote in the state senate was 28-2.

Last week, Governor Peter Shumlin, a Democrat, signed the bill, which stands to make Vermont the first state in the country to require foods sold within its borders to indicate on their labels whether they contain genetically modified ingredients. Activists hailed the move. “The biggest victory, the watershed victory, has taken place with the signing of the legislation in Vermont,” says Ken Cook, president of the the D.C.-based Environmental Working Group.

Vermont is first, but it is unlikely to be the last. The push to label GMOs is the subject of a burgeoning, passionate national movement. There are currently 84 bills on GMO labeling in 29 states, according to the National Conference of State Legislatures, as well as dueling bills in Congress. Earlier this year, Maine and Connecticut passed labeling requirements contingent on a “trigger” mechanism: The requirements won’t take effect unless several neighboring states take the same step. Labeling referenda were defeated in in California in 2012 and Washington in 2013. But activists are attempting to put the issue on the ballot in a fresh crop of states this year, including Oregon, Colorado, and Arizona.

In state after state where labeling has been proposed, the politicians pushing it—mostly Democrats—tell the same story. The issue, they say, was hardly on their radar until a massive amount of constituent pressure put it there. In Vermont, the campaign for labeling was spearheaded by a coalition of organic farms and the Vermont Public Interest Research Group. Campaigners knocked on 80,000 doors and got 30,000 Vermonters to send postcards to their state legislators.

Labeling proponents have focused their message not on attacking GMOs themselves but on consumers’ right to information. “This bill is not a judgment about whether you should or shouldn’t eat foods that are GMO-based,” Shumlin told me. “We’re simply saying when you read the ingredients of what you buy, you ought to be able to know if you’re eating a GMO-based product.”

Children in Los Angeles take part in a worldwide “March Against Monsanto” on October 12, 2013. (Lucy Nicholson/Reuters)

No widely accepted science supports the idea that GMOs are inherently dangerous to people’s health or the environment. To proponents, including many in the agribusiness industry, opposition to GMOs is nothing more than a dangerous mania, and the people in the grip of it are akin to those who refuse to vaccinate their children or who deny that human activity is changing the Earth’s climate.

Yet the grassroots fervor around the topic—driven by Internet rumors, liberal anti-corporatism, and mothers concerned about their children—is undeniable. More than a million people have signed a petition to the Food and Drug Administration asking it to label GMOs, the most of any petition in the agency’s history. “Members of Congress are being asked by their constituents to take a stand on this issue,” says Colin O’Neil, director of government affairs for the pro-labeling Center for Food Safety in Washington, D.C.

In the wake of Vermont and other state efforts, the food industry, whose profits now depend on GM ingredients, is clearly panicked by the potential for a 50-state patchwork of conflicting labeling requirements that could force manufacturers to package, say, potato chips differently from one state to another. (An estimated 60 to 70 percent of processed foods contain GMOs.)

The industry has struck back with a bill in Congress that would put labeling of “biotechnology”—the food industry’s preferred euphemism for GMOs—solely in the hands of the FDA and prohibit states from requiring it. The industry-backed bill faces long odds in a gridlocked Congress; its introduction, last month, was mostly a symbolic act by GMO proponents hoping to counter the other side’s momentum.

The bill’s chief sponsor, Republican Mike Pompeo of Kansas, sounded exasperated when I asked him about the passion surrounding labeling. “There was [passion] around Alar too, right?” he says, referring to the apple spray taken off the market in the 1980s after what growers viewed as an alarmist campaign by environmentalists. “We’ve had people create food scares not based on science many times in the history of the United States. This is not a new phenomenon.” I spoke to Pompeo the day after he introduced the bill. He estimated he had already received 500 phone calls—overwhelmingly from opponents.

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Natural-food advocates have been trying to curtail the rise of GMOs in America since regulators first approved them, two decades ago. In 2002, a ballot initiative for GMO labels failed in Oregon. The current push appears to have been set off in 2012, when activists in California—the state where seemingly every issue lands on the ballot—brought an initiative to require GMOs be labeled on products sold in the state.

“Me. It was me,” Pamm Larry, a grandmother and former midwife and herb farmer from Chico, tells me with a laugh. “I started it.” She’s not exaggerating: The idea for a ballot initiative came to her in a dream one night in 2011—January 21, 2011, to be exact. “It hit me that it was time for the people of California to vote,” she says.

Many national anti-GMO activists opposed her gambit. They didn’t think the time was ripe; they worried a defeat would be a setback from which the movement couldn’t recover. Larry, who cheerfully admits her lack of political expertise, was not deterred. She recruited like-minded activists on Facebook and at organic stores and farmers markets, crisscrossing the state in her 1998 Toyota Camry with “GMO OMG” license plates. The volunteers began circulating a petition in February 2012, and in 10 weeks, they had nearly a million signatures.

In retrospect, the triumphant signature-gathering effort may have been the campaign’s high point. Proposition 37, as the initiative was eventually called, was supported by the California Democratic Party and the Green Party. But it immediately ran into a barrage of confusing and expensive ads funded by Monsanto, the Missouri-based biotech giant, and others in the food industry. Monsanto’s financial interests are clear: Its GM seeds account for 80 percent of the corn and 93 percent of the soybeans grown in the U.S.

By the time the California election was over, opponents would spend $46 million on the campaign—$8 million from Monsanto alone, along with multimillion-dollar contributions from DuPont, PepsiCo, Kraft Foods, and other food-industry giants—versus proponents’ $9 million. Public support dropped precipitously as ads claimed labeling would lead to higher food prices. The measure failed, 51 percent to 49 percent.

Proposition 37 may have lost, but to Larry, it scored a moral victory. The initiative unleashed a tide of pent-up national interest in GMOs and labeling. Activists in other states, surprised and angered by its defeat, rushed to take up the cause, spawning today’s impressive spate of legislative proposals and referenda. Nor is the fight over in California, where previously reluctant state legislators recently voted a labeling bill through two state-senate committees. “We are already winning,” Larry says. “More people are paying attention to this issue.”

Demonstrators in New York dress up as tomatoes during an anti-GMO march on May 25, 2013. (Eduardo Munoz/Reuters)

It’s still not clear, however, whether labeling proponents can muster the funding and political savvy to win at the ballot box. The story of Proposition 37 played out in almost exactly the same way the following year in Washington state. Once again, a ballot measure was undertaken by a lone activist who used the Internet and the statewide network of health-food stores, organic grocers, farmers markets, and natural-food activists to find allies. The measure, known as Initiative 522, was put to a vote in November 2013. Conditions were far from ideal: The off-year timing ensured that turnout would be extremely low. Once again, an avalanche of ads sponsored by pro-GMO industrial interests quickly shifted the tide of public support, and the measure narrowly lost.

“Monsanto was writing million-dollar checks at a shot,” recalls Trudy Bialic, the public-affairs director of a Seattle-based natural-foods co-op chain, who helped draft the initiative. The Grocery Manufacturers Association, the lobby for makers of processed food, donated $11 million. “Boom, boom, boom, millions overnight. It was death by a thousand cuts—[the opponents] confused people, but they never addressed the central issue of a consumer’s right to know. And we still almost won.”

GMO proponents will tell you that this picture of a movement of scrappy activists pitted against the menacing behemoth of Big Food isn’t totally accurate. Labeling is backed by its own special interests, chiefly the organic and natural foods industries, which would presumably see their market share increase if consumers suddenly confronted GMO labels on grocery shelves. Major financial backers of labeling include organic-food manufacturers such as Amy’s Kitchen and Nature’s Path, the organic-soap company Dr. Bronner’s, and the dietary-supplement marketer and vaccination critic Joseph Mercola. The campaign for labeling isn’t purely activist-driven—it’s a coordinated national effort on the part of groups like the Center for Food Safety and Just Label It, a project of the Environmental Working Group. The national groups aid local activists with resources and strategy.

But these interests are dwarfed by several orders of magnitude by the size and clout of the agribusiness industry on the other side. There’s no mistaking who is the grassroots David and who is the big-business Goliath in this fight.

The groundswell for labeling is genuine and impressive. Last year, activists in hundreds of U.S. cities undertook a “March Against Monsanto” to protest GMOs, drawing hundreds of thousands of protesters. A follow-up march is planned for later this month.

Eduard Korniyenko/Reuters

When Kristi Marsh began treatment for breast cancer in 2006, toxic chemicals—chemotherapy—saved her life. But the stay-at-home mom from the suburbs of Boston underwent an awakening to the toxicity she suddenly saw all around her, slowly and surely and silently poisoning her body and those of her three young children.

Marsh decided to take back control. She began eliminating worrisome substances from her household, starting with cosmetics and cleaning products, then proceeding to GM foods. “I went from living a life of mainstream consumerism to making a conscious decision to put health first and allowing that to guide all my decisions,” is how Marsh explains it to me. “I just turned my whole life and my house inside out.”

In her book clubs and among her neighbors, Marsh was constantly answering questions from her fellow moms. At first, the idea that she could be an expert seemed ridiculous. “I admit I’m not a scientist. I don’t know how to answer what’s going on out there,” she says. But when she asked people who seemed like they ought to have expertise—scientists and legislators and people with Ivy League degrees—they didn’t seem to know either. “In the end, I feel no one knows the full answer,” she says. “What I tell women is, that’s not your fault. The whole point is it’s a huge unknown and we know enough to do something about it. It’s not me—the whole world is trying to figure this out.”

Much of the activism against GMOs has come from people like Marsh: impassioned, not particularly politically oriented citizens, often women, who find each other through the Internet. The successful campaign for Connecticut’s trigger-dependent labeling bill this year was led by a self-described “mom on a mission,” Tara Cook-Littman, who’s now seeking to capitalize on her following by running for the state legislature as a Democrat. The Proposition 37 campaigners were dubbed an “army of moms” by the media. Many consider themselves heirs of the 1870s Pure Food Movement, which was led by women’s groups and resulted in America’s first regulations on slaughterhouses.

Marsh had always had a passion for public speaking, and she began taking Toastmasters classes and putting together a talk about everyday toxins. Soon she was drawing big crowds and addressing important audiences: the nurses and doctors at Boston’s prestigious Brigham and Women’s Hospital, a women’s luncheon at Purdue University, local chambers of commerce, the 65,000-attendee Natural Products Expo in Anaheim, California. A self-published book about her journey, Little Changes, has sold thousands of copies around the world, she says.

Marsh and I are talking in a coffee shop in downtown D.C., where she has come for a meeting with senators on reforming the Toxic Substances Control Act. She opens a recent copy of The Atlantic to an ad for the annual Aspen Ideas Festival, cosponsored by The Atlantic and the Aspen Institute, which indicates that one of the underwriters is Monsanto. Because of that, she says gravely, she was afraid to meet with me. (Sponsors and advertisers are not involved in The Atlantic’s editorial decisions, and I was not aware of the business relationship until Marsh noted it.)

Marsh is unperturbed by critics’ charge that she and her fellow activists aren’t following science. “That’s fine, they can think that,” she says. “What I know is that food and health, to me, is one. What has happened in the last 20 years is just crazy. For people to mess with my food without ever letting me have a say in the matter before I feed it to my children—the trust is blown right there.”

Marsh has called and met with her state and local lawmakers, staged an “eat-in” at the FDA, and marched on the state house in Boston. (A labeling bill—one of five considered by the Massachusetts legislature this year—recently advanced out of committee.) But she is not a political person, she says, and doesn’t have a goal for what she’d like to see in terms of GMO policy. “What I am doing is connecting women and letting them know that it’s OK to be the advocates for their own bodies,” she tells me. “It exists inside them. I’m just waking it up: that tiny voice that’s been pushed down for decades by marketing, that says This is what you should buy, this is how you should act.

The response, in communities across the country and her devoted online following, has been an outpouring of sentiment. “If politicians are just starting to hear about this, that’s not because it’s just starting to happen,” Marsh says. “It exists. It is passionate. It is powerful. People want to understand what they’re putting on their table, and it’s just a matter of how long they’re going to keep fighting us.”

Activists stage an “eat-in” outside the U.S. Food and Drug Administration’s Center for Food Safety and Applied Nutrition in College Park, Maryland on April 8, 2013. (Gary Cameron/Reuters)

The GMO debate has a frustrating quality, with one side decrying big corporations out to deceive us and the other pointing the finger at unscientific fearmongering. Both of these lines may be true as far as it goes; what the debate comes down to is politics.

Though opposition to GMOs has its roots in the liberal environmental movement, an increasing number of environmental writers and thinkers have begun to take the industry’s side in the debate, pointing to an overwhelming scientific consensus—based on hundreds of independent, non-industry-funded, peer-reviewed, long-range studies—that GMOs are safe. The scariest recent study, which claimed that GMOs caused tumors in rats, was the work of a rogue laboratory in France whose findings have been widely debunked. The National Academy of Sciences, the American Medical Association, the World Health Organization, the U.K.’s Royal Society, the European Commission, and the Center for Science in the Public Interest have all sought to weigh GMOs’ purported risks, and found that there is no evidence they are dangerous.

And yet GMOs are the subject of widespread fear and antagonism. University labs accused (not always accurately) of conducting GMO research funded by Monsanto have in the past been burned down by eco-terrorists. This type of sabotage has been rare in the past decade, but it may be making a comeback: Last year, a field of GMO sugar beets in Oregon was destroyed by vandals. Scientists and journalists who voice pro-GMO opinions are accustomed to being dismissed as industry shills, personally vilified, and even receiving death threats. Headlines on food blogs warn of “mutant GMO foods.” In the D.C. area, a car topped with a giant half-fish, half-tomato—the “fishy tomato”—roams the streets; the car’s hood reads “LABEL GMO FOOD.” In the popular imagination, GMOs are scary.

Labeling proponents dispute the idea that they’re bucking a scientific consensus akin to the consensus about global warming or about vaccine safety. “I know dozens, personally, of scientists from all kinds of backgrounds—from neurobiologists to systems ecologists to entomologists—who have serious questions about [GMO] technology,” Doug Gurian-Sherman, senior scientist for the Union of Concerned Scientists, told me recently. Gurian-Sherman acknowledged that his concerns are chiefly about “how the technology is being developed and regulated” and revolve around environmental worries, not alleged effects on human health. He and other environmentalists principally object to the long-term unsustainability of the industrial food system, of which GMOs are merely a part.

But the effect of GMOs on the environment is debatable. GMOs have become an inextricable part of the large-scale agricultural system environmentalists decry, but that does not mean GMOs are to blame for it. Nathanael Johnson, a reporter at Grist, examined GMOs’ environmental impact and concluded that they have both decreased the use of toxic insecticides and increased the use of herbicides—the most common GM crop in America, Monsanto’s “Roundup Ready” corn variety, is immune to the herbicide glyphosate. As The New York Times’ Mark Bittman wrote last week, “If anti-G.M.O. activists were successful in banning G.M.O.’s, we’d still have industrial agriculture, along with its wholesale environmental degradation and pollution, labor abuse and overproduction of ingredients for the junk food diet.”

Proponents of GMOs—who tend to be pro-industry conservatives—bemoan the media’s unwillingness to police the biotechnology debate, just as environmentalists once protested false equivalence in coverage of climate change. “We shouldn’t allow people to go around making claims and have the media report those claims as, 'Well, some say yes and some say no’ when the claims are totally false,” Pompeo, the Republican congressman, laments. “That’s not reporting.” The president of the American Farm Bureau, Bob Stallman, fretted to me in an interview at the bureau’s annual convention earlier this year, “Unfortunately, our society is not that well educated in science anymore. It’s a sad fact: They believe what they read on the Internet.”

But if GMO proponents have a credibility problem, it’s largely self-inflicted. Many of today’s aggressive proponents of GMO science were yesterday’s global-warming deniers. Stallman’s Farm Bureau spent years hotly contesting climate science, including a 2010 convention session titled “Global Warming: A Red Hot Lie?” Industry-funded think tanks like the Heartland Institute and the Competitive Enterprise Institute, both long known for their climate skepticism, have both recently been promoting GMOs. (Pompeo, for his part, believes that warming is occurring but that it's not necessarily anthropogenic, according to a spokesman.) Mailers and television ads opposed to California’s 2012 labeling referendum featured a scientist affiliated with the conservative Hoover Institution who had previously denied there’s a link between cigarettes and cancer.

Niloo/Shutterstock

And so there is plenty of hypocrisy and bad faith to go around where science is concerned. “The emotionally charged, politicized discourse on GMOs is mired in the kind of fever swamps that have polluted climate science beyond recognition,” the environmental writer Keith Kloor wrote in a Slate article that proclaimed GMO opponents “the climate skeptics of the left.” Mark Lynas, a former anti-GMO activist who now considers GMO fears a “conspiracy theory,” notes that GMO opponents use the same rhetorical tactics beloved of climate deniers: cherry-picking evidence, emphasizing a few dissenting “experts” over the scientific consensus, and attempting to “capture and control the public-policy agenda to enforce its long-held prejudices.”

To escape this maddening debate, labeling proponents have claimed that their cause doesn’t rest on what you think about GM food at all. Instead, they say it’s about consumer choice and the public’s right to know. “I firmly believe that Americans have the right to know what’s in their food,” Vermont’s Shumlin told me, adding that he was “not passing judgment.” Peter DeFazio, a Democratic congressman from Oregon who’s introduced a federal mandatory-labeling bill, adds, “There’s multiple sides to the issue, but the point is, there should be full knowledge available to consumers of the end product.”

“People get caught up in arguments about science, but labeling is not about the science of food,” Bialic, the Seattle activist, says. “Food labeling in this country has never been about science. It’s about what is of material concern to the consumer.” In the 1980s, she notes, the FDA mandated labeling of foods that had been irradiated not because they were thought to be unsafe but because thousands of consumers demanded it. Industry similarly fought mandates for ingredient disclosure and labeling of natural and artificial dyes and flavors, but their advent didn’t seem to scare consumers away from processed food. Labeling meats by their country of origin similarly satisfies consumers’ desire to know without being prompted by safety concerns. “It’s the consumer’s interest in knowing,” Bialic says. “All these arguments about science are an intentional distraction.”

Politicians especially like this line, as it enables them to wiggle out of taking a side on the GMO debate. And it is neatly tautological: Consumers deserve to know because consumers want to know.

But views on labeling are impossible to separate from the larger GMO debate. For proponents, labeling is just the first step toward reducing the prevalence of GM foods. For seed manufacturers and makers of processed foods, it’s a direct attack on their business. If either side believed a label would have no effect on the dynamics of the food system, they wouldn’t be fighting over it so hard.

Opponents of labeling fear that because GMOs and their safety are poorly understood, labeling will frighten consumers away from biotech foods for no reason. This is the argument made by agribusiness: “We support honest and truthful labeling that gives people information they can use,” says Natalie Rosenbloom, Monsanto’s vice president for sustainability. “The concern with mandatory labeling is that it’s not really based on any safety issue with the food.” Monsanto blames itself for some of the antagonism to GMOs: Rosenbloom says the company’s lack of engagement and transparency in the past have allowed “misinformation” to spread.

In 2007, then-Senator Barack Obama made a vague campaign pledge to “let folks know whether their food has been genetically modified.” But the Obama Administration’s line on labeling has been closer to the food industry’s talking points. (As Jason Zengerle recently noted in The New Republic, labeling is one of many fronts on which food activists feel let down by the Obama presidency.) Agriculture Secretary Tom Vilsack told me in a recent interview, “When we require a label on something, we’re either warning there’s a potential safety problem or we’re giving nutritional information. GMO labeling doesn’t fit. There’s not a safety issue, and it doesn’t affect nutrition—it’s about the process through which food is created.” Requiring labels, he says, runs the risk of conveying “the intentional or unintentional message that this is unsafe or there’s some issue.”

In February 2014, protestors in Montpelier, Vermont, march to the statehouse to hear Monsanto lobbyists testifying before the House Agriculture Committee. (Toby Talbot/AP)

If you truly believe GMOs are innocuous, it’s hard to see a justification for requiring them to be labeled. But of the dozens of labeling advocates I’ve spoken to, I have yet to find one who doesn’t on some level doubt that GMOs are truly safe.

Public opinion is overwhelmingly in favor of disclosure. A New York Times poll last July found 93 percent of Americans want GMOs labeled. In Vermont, multiple polls on the labeling bill found public support of upwards of 70 percent. GMO proponents believe the public is simply ill informed and that support is soft. In California and Washington, they note, public opinion changed when people were exposed to more information—in the form of millions of dollars of frightening and often misleading campaign ads. Yet after the votes in those states, exit polls still showed majority support for labeling. The same electorates that rejected the labeling ballot measures still supported GMO labeling as a concept.

After last November’s defeat of the Washington ballot initiative, the food industry saw an opening. The Grocery Manufacturers Association announced in a press release the next day that it would seek federal action. But Pompeo’s bill, the action the association promised, would not be introduced for five more months due to industry lobbyists’ wrangling behind the scenes over the particulars.

“GMA wanted to have this introduced as soon as last November’s ballot initiative in Washington State failed in order to capitalize on the momentum,” a top agribusiness lobbyist who spoke on condition of anonymity told me. “But it took much longer than expected for all of the stakeholders to agree upon language and strategy.” In the intervening months, Connecticut and Maine passed their trigger-dependent labeling bills, and Vermont’s bill proceeded toward passage. Some labeling opponents view the delay of the Pompeo bill as a missed opportunity to send a signal to states that the federal government was taking action. Their fear is that they may have missed their chance to head off state legislative efforts.

Issue watchers consider federal action unlikely in the near future—in either direction. DeFazio’s mandatory-labeling bill, introduced jointly in the Senate by California Democrat Barbara Boxer, has gone nowhere. In January, shortly after Cheerios announced it would go GMO-free, four Democratic lawmakers joined with green and organic-industry groups in signing a letter urging President Obama to support labeling. But the administration has stuck to a stance that pleases neither side: opposed to labeling, but also much slower to approve new GM crops than the agribusiness industry would like.

Labeling opponents don’t expect federal action, either. Pompeo’s bill is expected to get a hearing in the House next month, but he’s girding for a long fight. In addition to preventing states from requiring GMO labeling, the bill would require any proposed biotech food to be reviewed by the FDA, a measure he touts as an increase in GMO regulatory oversight and one that he says should please GMO opponents. Currently, this authority is split between the Environmental Protection Agency and the U.S. Department of Agriculture. “We’ll keep grinding until we get there,” Pompeo told me, adding that he’s received support for his bill from both sides of the aisle.

After Shumlin signed Vermont’s labeling bill into law last week, the Grocery Manufacturers Association announced that it planned to “file suit in federal court against the state of Vermont to overturn the law.” A potential lawsuit is expected to focus on claims that state-based mandatory labeling violates the principles of commercial free speech and interstate commerce. Shumlin told me he expects the law to survive, noting that in anticipation of just such litigation lawmakers included $1.5 million in funding to defend the law in court. “We think we’ve written a really solid bill that has the best chance possible of standing up in court,” Shumlin told me. If that’s the case, Vermont’s labeling requirement will take effect starting in 2016.

Meanwhile, more state legislatures are poised to consider the issue, and petition drives are underway put the issue on the ballot in more states. It is an indiscriminate fire hose of activity.

Labeling proponents on the national level are trying to become more strategic. “We’re trying to act as a coordinating forum for states to talk to each other and share information,” particularly about how to deal with attacks from the opposition, says Gary Hirshberg, cofounder of the organic yogurt maker Stonyfield Farm and chairman of Just Label It. “It’s clearly a synergistic relationship between state and federal activists.” While state-level activists agree that a federal solution would be ideal, other movements, Hirshberg adds—from women’s suffrage to same-sex marriage—show that “often states have to take the lead when the federal government is not functioning.”

The Oregon initiative, which closely mirrors the Vermont law, was approved by the state’s supreme court last week. Organizers now have until July 3 to collect 87,000 valid signatures. Paige Richardson, the campaign director for Oregon Right to Know GMO, says she’s confident it will qualify and fare better at the ballot box than its predecessor 12 years ago. Oregon campaigners have learned from previous mistakes, she says, and from observing labeling opponents’ tactics. While there’s no way the campaigners will be able to compete financially with the resources of Monsanto and the food industry, they hope to run a savvier and better-funded campaign. “This issue has caught everybody by surprise,” Richardson told me. “It’s hitting a threshold.”

Strong national backing for the Oregon campaign has left activists in other states grousing that they’re not getting similar support. In Colorado, the state supreme court has approved a labeling initiative, and a signature-gathering effort, which has until August 4, is being run by volunteers operating out of Vitamin Cottage stores and farmers markets. Rick Ridder, a political consultant advising the effort, says it’s rare for referenda to qualify for the Colorado ballot without paid staff—meaning labeling will need a true grassroots groundswell.

In Arizona, signatures are being gathered by Jared Keen, a Tucson-based “plant-based diet” advocate who lost 120 pounds after he eliminated processed foods starting in 2011. Keen told me he appealed to national groups such as the Center for Food Safety for support, but they refused because they are focused on Oregon. But Keen thinks Arizona is ready. There are five “GMO Free” activist groups across the state helping gather the 173,000 signatures needed by July 3.

“We have no money,” Keen told me. “It’s all volunteers.” But there has been a broad-based outpouring of support, which he sees in his health talks around the state. “I talk to Tea Party people, Occupy people, churches, everybody,” he says. “Everywhere I go, all parts of the state, people want labeling. There are very few people who don’t want to have a say in this issue. Once we get the signatures, I know it will pass.”

Despite Keen’s optimism, in reality, it will not be surprising if his effort—underfunded and without national support—falls short. But the larger movement of which he is a part seems to be gaining momentum. Previous losses have only strengthened activists’ resolve, just as the defeat of Proposition 37 in California was the progenitor of today’s dozens of labeling initiatives. The fight to label GM foods may not have science on its side, but in the political arena, it is quickly gaining ground.