A decision in the administrative law case Monsanto Company v. Durnell, which the Supreme Court will hear on Monday, will have sweeping effects for the future of the Make America Healthy Again movement.
Justices will hear from Bayer, the parent company of Monsanto and the maker of the weedkiller RoundUp, as to whether the company should be held liable for not including a warning about potential cancer risks on its label.
The case itself involves highly technical concepts related to administrative procedure law and federal versus state authority, focusing on the degree of authority that experts at the Environmental Protection Agency have to set nationwide product labeling standards. It is also a test for the MAHA movement’s relationship with the Republican Party ahead of the midterm elections this November.
Glyphosate, the main ingredient in RoundUp, has long been a target for health and wellness advocates, who blame the chemical for causing not only cancer but also widespread endocrine and metabolic disruption.
But in what MAHA advocates describe as a betrayal of the movement, the Trump administration is arguing on behalf of Bayer in the case, saying that the EPA has final authority on what is included on product warning labels.
Here is everything to know, from the ins and outs of the case to the political consequences for the GOP.
RoundUp, Glyphosate, and the case
Glyphosate, a non-selective herbicide, is the most commonly used weedkiller in the United States. Each year, roughly 280 million pounds of glyphosate are sprayed onto the nearly 300 million acres of U.S. farmland, according to the EPA. The chemical is used both as a weedkiller and as a desiccant, used to kill grains to make harvesting easier for farmers.
The EPA first reviewed and registered glyphosate-based pesticides in 1974, periodically reviewing the chemical’s safety and finding that it does not pose a public health risk. The EPA has also continued to approve the product label without mention of cancer risks.
In 2015, a working group of the International Agency for Research on Cancer from the World Health Organization conducted a broad review of research on glyphosate and classified the herbicide as “probably carcinogenic to humans.”
That finding kicked off a plethora of lawsuits against Monsanto from Americans who had been diagnosed with non-Hodgkin’s lymphoma after using RoundUp, resulting in billions of dollars in liabilities found against the company by civil juries across the country.
John Durnell, who believes glyphosate exposure triggered his cancer, first sued Monsanto in 2019 in Missouri, which has strong state regulations on product warning labels.
Durnell was awarded $1.25 million in damages by a jury from Monsanto for his failure-to-warn claim, and since then, all lower courts have sided in his favor.
After the Missouri Supreme Court declined to take the case, Monsanto asked the federal Supreme Court to weigh in. In December, U.S. Solicitor General D. John Sauer asked the justices to hear the case, and the Court added it to its docket in January.
Federal versus state authority on health and safety
Bayer contends, under the Supremacy Clause of the Constitution, that federal regulations on product labeling established under the Federal Insecticide, Fungicide, and Rodenticide Act, or FIFRA, give the EPA the final authority on labeling requirements for herbicides and pesticides under its jurisdiction.
Specifically, the company points to a provision in FIFRA that says a “State shall not impose or continue in effect any requirements for labeling or packaging in addition to or different from those required under” federal law.
Bayer’s argument relies on precedent in PLIVA Inc v. Mensing, a similar case involving adverse reactions to generic medications approved by the Food and Drug Administration.
In that 2011 case, the FDA label for the drug metoclopramide, known by the brand name Reglan, did not include a warning that long-term exposure could cause a severe neurological disorder. The label was eventually changed by the FDA in 2009 after accumulating evidence, triggering numerous lawsuits against the maker, PLIVA.
The Supreme Court ruled in PLIVA that the FDA had the ultimate authority to decide what got put on drug labels, finding the company not liable for not warning patients sooner about potential side effects that were not recognized by the agency.
Bayer’s counsel believes the company’s case on glyphosate is similar, with EPA holding the sole authority for product labeling that falls under FIFRA.
“Inadequate warning” provisions in federal law
Durnell and his attorneys, however, use a different provision in FIFRA for their argument to conclude the company has a legal obligation to not misbrand its product under federal law.
One section of the law prohibits misbranded pesticides, the definition of which includes having a label that “does not contain a warning or caution statement which may be necessary” to “protect health and the environment.”
Durnell argues that this provision effectively matches state laws that forbid the sale of pesticides and herbicides without “adequate warning.”
Lower courts have tended to side with Durnell on this point. The Missouri Court of Appeals in February 2025 affirmed Durnell’s initial judgment and held that Monsanto failed to show that Missouri’s labeling requirements were at odds with FIFRA regulations.
“The record contains no evidence that Monsanto either informed the EPA of the justifications for a change to its warning label or that the EPA has informed Monsanto it would not approve such a warning,” the court explained.
Bayer disagrees, saying that Congress wrote FIFRA to “ensure ‘uniformity’ in labeling” across the country rather than create ambiguity in labeling requirements based upon the findings of particular juries.
MAHA and the GOP
The Trump administration’s support of Bayer in the case has strained the fragile relationship between MAHA and the Republican Party, a partnership that some analysts credit with President Donald Trump’s 2024 victory.
In February, Trump issued an executive order declaring domestic glyphosate production a national security priority and granted liability immunity to Bayer to ramp up manufacturing.
Shortly after the executive order and the Supreme Court agreed to hear Monsanto v. Durnell, Bayer announced a proposed $7.25 billion settlement to resolve “current and future cancer lawsuits” over RoundUp, including ones that would be foreclosed should the Court rule in the company’s favor.
MAHA activists have increasingly put pressure on Health and Human Services Secretary Robert F. Kennedy Jr. for, in their view, betraying the movement. Kennedy, an environmental lawyer who was involved in some of the first litigation against Monsanto, has walked a tightrope in recent weeks to avoid alienating the MAHA base.
During his testimony in Congress to defend Trump’s 2027 budget proposals, Kennedy redoubled his support for the president’s executive order, saying that protecting domestic manufacturing for glyphosate is necessary while farmers are still “addicted” to the herbicide. Kennedy also said last week that Trump “has invested more in trying to transition off of glyphosate than any other president,” citing $200 million in funding for his department to research regenerative agriculture.
But it’s not enough for many activists, especially so-called “MAHA moms” at the heart of the movement.
A Politico poll from early April found that 51% of voters say the Trump administration is falling short on its promises to make the country healthy again. That includes 53% of women voters.
The poll also found that seven in 10 women support limiting pesticide use, including four in 10 who strongly support it.
Food activist Vani Hari, known as the “Food Babe,” and several other advocacy groups across the political spectrum have organized a protest outside the Supreme Court to coincide with oral arguments to express displeasure in the administration’s handling of the case. More than 1,000 people are expected to attend the rally.
MAHA TO PROTEST OUTSIDE OF SUPREME COURT OVER ROUNDUP CASE
Hari told the Washington Examiner in an interview before the rally that the Trump administration “made this an issue” because of their involvement in the glyphosate case.
“If they had just sat back and let Bayer fight their own fights, they wouldn’t have been involved in this situation right now,” said Hari.