Mexican farmer Arnulfo Melo show harvested corn from his organic corn field

Farmer Arnulfo Melo shows harvested corn from his organic field in Milpa Alta, Mexico, on October 18, 2021, months after the Mexican government banned genetically modified corn for human consumption

(Photo: Rodrigo Arangua/AFP via Getty Images)

Law Is Not on the US Side in GMO Corn Fight With Mexico

Put simply, the U.S. gets it wrong when it comes to trade rules on food safety. Their lawyers—experienced as they are—should know better.

The United States ups the ante in its legal clash with Mexico over genetically modified (GMO) corn. Last month, a trade panel released the US’s latest legal filing. It essentially doubts the science Mexico offers and claims Mexico violates obligations from the USMCA trade pact.

This regards Mexico’s Decree from April 2023 banning GMO corn for human consumption. The ban cites harms from genetic manipulation of corn seeds and cancer risks from herbicides like glyphosate, needed by GMO farms. A USMCA panel will hold hearings on American complaints in June.

The U.S. position is not as strong as it claims—far from it. Observers analyze why Mexico’s scientific justifications are on solid ground. As a law professor, I explain how the U.S. overstates its legal case, at times severely so, when it comes to the ban on GMOs in tortillas and masa (dough).

Put simply, the U.S. gets it wrong when it comes to trade rules on food safety, called sanitary and phytosanitary measures (SPS) and covered in USMCA Chapter 9. Weaknesses regard two aspects of food safety: protection levels and health risks. In a recent journal article, I offer detailed examinations of these and other obstacles.

American faults involve established international law. The USMCA is three years old and this case raises its first SPS controversy. Fortunately, there are long-settled understandings in international law specific to SPS and trade obligations. For decades, panels have interpretated the World Trade Organization’s (WTO) SPS Agreement. This will inform the USMCA panel.

SPS Agreement obligations are central to the USMCA. In the new trade pact, the U.S., Mexico and Canada expressly agreed to affirm “rights and obligations” from the SPS Agreement. Numerous tribunals have ruled on disputes about the SPS Agreement. They’ve examined food safety measures and impacts on trade in food and agriculture, similar to gripes concerning Mexico’s Decree.

Both sides refer to panel reports from SPS cases. Reports are like court opinions. The U.S. cites over 40 reports, including 16 from the highest level, the WTO’s Appellate Body. Mexico references nearly50 and 23 from the highest level. The U.S. problem : it excludes important legal aspects from these reports.

One omission regards what is called the “appropriate level of protection” (ALOP). The USMCA uses the WTO definition for ALOP: the “level of protection deemed appropriate” by the country establishing a measure to protect human life.

The U.S. gets it wrong in terms of what this level can be and who determines it, to then say Mexico inadequately defines it. Mexico is clear that for human consumption of GMO corn, its ALOP is “zero risk.”

The U.S. may not like this, but it is legal under trade rules. This is irrefutable. In 1998, the Appellate Body found “zero risk” is permitted for an ALOP. This comes from a controversy between Australia and Canada over salmon imports. In the corn dispute, the U.S. refers to the case but not to its sections approving “zero risk” levels.

This is forgetful lawyering. Trade law treatises describe “zero risk” as a settled option and interpreted as such by later trade panels. Like legal encyclopedias, treatises summarize how legal doctrine develops, based on new rulings. Attorneys and judges use them to identify how courts and panels interpret legal rules. For ALOP, American lawyers fail with the basics.

The US underplays who actually determines the ALOP. Mexico does, according to the USMCA. Trade rules are explicit that countries in situations like Mexico have wide discretion to determine the ALOP. This is “unambiguous.”

Prior cases are clear. In 2008, the Appellate Body said a country employing a food safety measure has the “prerogative” to determine the ALOP. This involved an American challenge to European Union (EU) controls of hormones in beef.

Second, the US exaggerates requirements in evaluating food safety, called “risk assessment.” Risk assessments are “evaluation[s] of the potential for adverse effects on human health.” This definition comes from the SPS Agreement and is incorporated by the USMCA. Mexico’s assessment is titled the “Scientific Record on Glyphosate and GM Crops” published in 2020 and available since then online from the National Council of Humanities, Sciences and Technologies (CONAHCYT).

The U.S. overstates what is legally needed, to then characterize Mexico’s assessment as “incoherent and inadequate.” WTO cases find that risk assessments must only establish a “potential” for adverse effects. The Appellate Body confirmed this standard in the US’s first challenge of EU controls for hormones in beef in 1998.

The standard has staying power. Ten years later, the tribunal re-affirmed this requirement in the U.S.’s second trade case against beef hormone regulations.

The standard is a fixture of SPS doctrine. Recent treatises explain that for risks in human food, trade rules are deferential to SPS measures since “protection of public health is at stake.”

In its legal filing, the U.S. demands far more than is legally necessary. It calls for excessive proof. This includes “estimates of hazard, exposure, or risk” and “levels that can cause” adverse effects when eating corn. It faults Mexico for not proving that imported GMO corn “presents unsafe levels of glyphosate residue.” These are a few examples that veer from what international trade law actually requires.

SPS cases on risk assessments further undercut American positions. In the first beef hormone controversy, the Appellate Body explained that food safety measures must have a “rational relationship with the risk assessment” and that risk assessments must “reasonably support” this food safety measure. This U.S. must have missed these trade rules, since it asks for significantly more from Mexico.

Emotionally, the U.S. presents criticisms of GMOs as fringe and unacceptable. The filing says that scientific evidence provided by Mexico only “distract[s] from prevailing scientific opinion.” This is demeaning.

Trade rules are more based on reason. They do not require SPS measures to reflect majority scientific opinion. Lawyers for the U.S. should know this. In the first fight over beef hormones, the report explained that assessments do not need to “embody” the “view of a majority” of the scientific community. Then with a second American try, the Appellate Body added that scientific support is acceptable as long as it is “considered to be legitimate science.”

Where does this take us? With legal lapses in several areas, the U.S. should try to resolve its gripes with Mexico versus pursuing fruitless disputes. The commercial reality is U.S. corn exports to Mexico have dramatically increased since the Decree.

Be careful what you ask for, when it comes to trade rulings. It is 2024 and trade lawyers for the U.S. eerily face the same legal questions from 1998 and 2008. Then they concerned American beef exports. U.S. lawyers should re-read those rulings. Trade law is clear on ALOP and risk assessments. American farmers don’t need another trade loss, they need better legal advice.

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