In late 2020, the Mexican government announced its intention to ban the import of genetically modified (GM) corn. Citing concerns about health, environmental impact and the cultural importance of corn in Mexico, where the crop originated, the announcement sparked an ongoing trade dispute with the U.S. that has raised questions about food sovereignty, free trade agreements and the role of genetically modified organisms (GMOs) in the food system.
Under intense pressure from Washington to repeal the measure, the Mexican government partially rolled back the ban in February 2023 to include only white corn, which is intended for direct human consumption, leaving yellow corn imports (almost entirely used for animal feed and industry) in place. But after that concession, Mexican President Andrés Manuel López Obrador vowed to not back down any further. After an initial round of talks ended in early April without an agreement, the U.S. has formally requested consultations under the United States-Mexico-Canada Agreement (USMCA), the free trade agreement that replaced the North American Free Trade Agreement (NAFTA) in 2020.
If those negotiations fail, a USMCA panel would determine whether the ban is justifiable in a resolution process that some anticipate could take all year. But such a decision would be confined to a discussion of scientific evidence about whether GM corn is harmful to human health. This is the ideal arena for U.S. agribusinesses, who have worked hard to promote the idea that any criticism of GMOs is irrational and anti-science, a position the Biden administration repeated in its own statements on the issue. In a debate confined to that front, Mexico is unlikely to win: With the majority of industry research dollars spent on new products rather than health and safety evaluations, the balance of existing evidence doesn't show direct harm from consuming transgenic material. This will hamper Mexico's health agency, Cofepris, from gathering the definitive evidence of harm that the panel is demanding.
Flattening the trade debate into one that's solely focused on the potential adverse health and safety of GM corn not only portends a loss for Mexico, but also excludes some of the real concerns that linger about GM crops regardless of whether consuming transgenic material is harmful. There are more pressing and scientifically validated worries about how GM crops have been deployed by agribusinesses, especially when it comes to excessive chemical use and biodiversity. And beyond the scientific sphere, the trade dispute raises tough questions about cultural identity, food sovereignty and the U.S.'s imperialistic relationship with Mexico — components that are unlikely to be reflected in a USMCA case.
A Tool in Irresponsible Hands
Today, most processed foods in the U.S. contain at least one genetically modified ingredient; most consumers are either unaware of this or not especially upset about it. That's a big shift from the early days of GMOs in the 1990s, when new products like the Flavr Savr tomato bombed after being labeled "frankenfoods." But as genetic modification quietly became commonplace for corn, canola, soy and other ingredients that people usually don't see or think about, the resultant apathy (or ignorance) laid the groundwork for agribusiness to brand any opposition to GMOs as unscientific — instead casting them as a necessary tool to feed a growing world. This is an easy enough thing to believe: Science writers often report on early-stage research promising to make plants use less water, photosynthesize more efficiently or even solve nutrient deficiencies. How could anyone be against that?
What's missing from this take is a critical eye toward what happens next: which GM crops get distributed and how they function as critical pieces of an industrial food system rather than offering an alternative to it. Much GMO skepticism is grounded in this justified mistrust of agribusiness.
To date, the most widely used genetic modification in corn is resistance to the herbicide glyphosate, a trait that makes it easier for farmers to spray an entire field without losing their crop. Conveniently, the same agrochemical companies behind the GM seeds supply those herbicides, making the package deal quite profitable for them — and ultimately propelling glyphosate from niche use to the most widely used herbicide in the world today.
Initially, glyphosate resistance was marketed as an environmental win, allowing farmers to phase out more dangerous herbicides. But with so much glyphosate being sprayed, unwanted plants developed their own resistance to it much quicker than expected, bringing many of the old herbicides back into popularity as farmers wage war against ever-stronger superweeds. Another popular modification — using bacterial DNA to give plants the ability to make their own insecticides — has fared slightly better, but insects, too, are evolving resistance to those toxins. Meanwhile, glyphosate has lost its reputation as mostly harmless: Chemical giant Bayer has paid billions to settle cancer lawsuits from people who handled Roundup and a mounting body of evidence shows that the compound is harmful to non-target insects and soil microorganisms.
The troubling relationship between GMOs and agrochemicals is a worldwide issue, but in Mexico, preserving biodiversity makes an even more compelling case. As the birthplace of corn, Mexico is home to more varieties than anywhere else on earth — and if farmers don't grow them, they're at risk of being lost forever. Even amid mounting pressure from their own government to adopt modern hybrid varieties under the banner of economic development, Mexican farmers have safeguarded native corn biodiversity by keeping thousands of traditional landraces under cultivation. In a future where shifting climate patterns and other uncertainties make agriculture less predictable, that diversity will be a boon for breeders.
No story proves this better than the buzz over a recently cataloged Oaxacan corn landrace: Its mucus-coated roots host communities of nitrogen-providing bacteria, a trait that could eliminate the need for resource-intensive nitrogen fertilizers. Geneticists have worked for years to develop similar traits in the lab, but it was smallholder farmers who had cultivated and preserved that corn for centuries. Ironically, if not for the farmers' tenacity, the pressure to adopt homogenous GM varieties could have wiped it out entirely.
What About Food Sovereignty?
The U.S. position on the trade dispute would suggest that — despite the 9,000-year history of corn in Mexico and its centrality to Mexican culture — any panic about GMO corn is the result of recent unscientific fearmongering. But beyond valid environmental and economic concerns, the factor of cultural significance raises an important question: Is science all that matters?
For the Indigenous people whose ancestors bred maize from the nearly unrecognizable teosinte, corn is much more than masa or animal feed, even retaining a religious importance for many farmers in Mexico. This attachment perseveres in spite of the deluge of cheap U.S. corn that's dominated the market since the implementation of NAFTA in 1994. In the decades since, corn imports from the U.S. have more than quadrupled — and while many smallholder farmers did leave farming as demand for domestic corn contracted, others have been reluctant to leave their land. Limiting U.S. corn imports might be their only path to survival and the only way to ensure the continuity of this significant part of Mexico's cultural heritage.
Constraining the USMCA negotiation to health and nutrition is a domineering and unfair move because it flies in the face of food sovereignty. Countries, communities and individuals have a right to choose what they want to eat. Science is just one of a host of influences that might factor into that decision, from personal taste to strongly held ideas about what kind of food system we want to support.
The U.S. does uphold the importance of food sovereignty, at least when it comes to ourselves, as we can see from one parallel (albeit less spiritually significant) issue: our attachment to cheap meat. Scientifically, it's undeniable that the factory farm system is bad for us and for the environment. But when climate scientists, nutrition experts or policymakers suggest changing anything, pundits accuse the government of "wanting to take our hamburgers." Alternative proteins, especially insects, inspire cries of "You can't make me eat that." Even among those who advocate a transition towards plant-based diets, the idea that we should ban animal agriculture outright isn't particularly popular. Regardless of what science has to say, all sides of the debate seem to understand that we can't tell people what to eat — an intensely held belief that has become a new flashpoint in the culture wars. With this and other contradictory food policies and guidelines in mind, it's ironic that the U.S. is now attempting to position itself as the arbiter of rational food choices.
The Real Debate: The Future of U.S. Agribusiness Dominance
So what's the real motivation here? On the surface, the dispute seems to be about business. Most parties critical of the ban have run with that angle, as with the headline of a recent article from the Genetic Literacy Project: "Mexico's proposed GMO corn ban could damage the US economy," a departure from the organization's typically sanguine, humanitarian-focused brand of GMO evangelism.
Mexico is the second-largest market for U.S. corn after China, buying nearly $5 billion of corn annually, which would have made the initial ban a very big deal. Critically, though, 95 percent of that imported corn is yellow and thus not subject to the modified version issued earlier this year. If implemented, its actual effect on U.S. farmers would be minimal.
$5 billion: The amount of U.S. corn bought by Mexico annually
This means the debate is largely symbolic and much more about the relationship between the U.S. and Mexico than the particulars of GM corn. As an Ohio State analysis posits, the real problem here is that the ban would introduce destabilizing uncertainty about the future of trade between Mexico and the U.S.. In other words, an economically insignificant concession to food sovereignty would threaten the U.S.-first order laid out under NAFTA and, later, USMCA, a more existential threat to U.S. agribusiness than a few missed shipments of white corn.
This trade dispute can be situated in a long history of economic policy that puts U.S. business profits over the needs of Mexican citizens. It's an imperialist stance that has made it easy for U.S. officials, then and now, to dismiss Mexico's concerns as quaint or irrational, even when the fears are more concrete. When Mexican farmers protested the implementation of NAFTA in the 1990s, they argued that cheap U.S. agricultural imports would flood the market and destroy traditions and livelihoods. And for many it did exactly that, with close to a million former farmers moving to cities or seeking work north of the border after the agreement was ratified.
This dispossession is one the Mexican government has sometimes been a partner in, with periods of unrestricted corn trade that weakened demand for domestically produced Mexican corn even further. But as Mexico now moves towards nationalizing other key industries like oil and electricity, it has an opportunity to minimize the influence of U.S. agribusiness on its economy. While this recent attempt to restrict corn imports would likely be found at odds with the terms of USMCA, it signals an important shift towards prioritizing food sovereignty in a trade environment that so often leaves small farmers and poorer countries, at a disadvantage.
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