The US Supreme Court is deciding whether glyphosate manufacturers must warn people their product may cause cancer.
The Trump administration is siding with Bayer. What does that tell us about who this system is designed to protect?
In 2023, a Missouri jury listened to the evidence and reached a verdict: Monsanto had failed to warn John Durnell that Roundup could cause cancer. They awarded him $1.25 million in compensatory damages. It was one of thousands of similar lawsuits — and one of more than 100,000 lawsuits filed by farmers, landscapers, gardeners, and everyday users who developed cancer after years of glyphosate exposure.
Bayer, which acquired Monsanto in 2018 and inherited its legal liabilities, has agreed to pay, paid, or provisioned billions in Roundup-related litigation to settle Roundup cancer claims. Then, in February 2026 — the same week President Trump signed his executive order protecting glyphosate production — Bayer proposed a further $7.25 billion class action settlement, bringing total settled or proposed liability to nearly $20 billion. Paid not because courts found the company innocent — but because the weight of litigation made settlement the more financially rational option.
Now Bayer wants the legal system to make sure it never faces another verdict like John Durnell’s again.
On April 27, 2026, the United States Supreme Court heard oral arguments in Monsanto v. Durnell. The question before the court is deceptively simple: does federal pesticide law prevent Americans from suing glyphosate manufacturers for failing to warn them of cancer risks — if the Environmental Protection Agency has not required such a warning?
If Bayer wins, the answer is yes. Tens of thousands of pending lawsuits could be dismissed. Many future failure-to-warn claims could be blocked or severely narrowed. And the company’s liability exposure — already reduced from what might have been hundreds of billions — would effectively be eliminated.
A decision is expected by the end of the Court’s term.
What Is Federal Preemption — and Why Bayer’s FIFRA Argument Could Silence Roundup Lawsuits
Bayer’s legal argument rests on a principle called federal preemption. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) — the US federal law governing pesticide labelling — requires that labels be approved by the EPA. Bayer argues that if the EPA has not required a cancer warning, then no state court jury can find a manufacturer liable for failing to include one. Federal law, in other words, should override state law — and by extension, override the ability of ordinary citizens to hold corporations accountable through the courts.
The argument has a surface plausibility. Regulatory consistency matters. Manufacturers should not face contradictory requirements across fifty states.
But here is what the argument actually means in practice: it means that Bayer’s liability for harm caused by Roundup is entirely dependent on what the EPA says — and the EPA, as we have documented in previous investigations, bases its assessments on industry-submitted studies, conducted using the kind of compromised laboratory animal models we examined in detail in our piece on animal model validity.
In other words: Bayer is asking the Supreme Court to rule that the same regulatory framework that relies on Bayer’s own safety data should also be the sole determinant of whether Bayer can be held legally responsible for the harm that data may have obscured.
The circularity of that argument is breathtaking. And the Trump administration is supporting it.
Trump’s Glyphosate Executive Order: National Security Cover — and a Hidden Liability Shield for Bayer
In February 2026, President Trump signed an executive order titled Promoting the National Defense by Ensuring an Adequate Supply of Elemental Phosphorus and Glyphosate-Based Herbicides. Invoking the Defense Production Act — the same legislation used to mobilise wartime industrial capacity — the order declared glyphosate a matter of national security, directing federal agencies to prioritise domestic glyphosate production and protect supply chains.
Bayer, it is worth noting, is not only the sole US producer of elemental phosphorus — it is also the only company producing glyphosate domestically in the United States, manufacturing approximately 40 percent of the global supply at its American facilities. The executive order, framed as protecting American food security and agricultural sovereignty, has the practical effect of entrenching Bayer’s position as an indispensable supplier to the American agricultural system.
What received far less attention than the supply chain provisions is what else the executive order contains: a liability shield. The Defense Production Act provision cited in the order provides limited immunity to domestic companies producing glyphosate and phosphorus under the order’s direction — meaning no person shall be held liable for damages or penalties for acts resulting directly or indirectly from compliance with the order. The executive order is therefore not merely a supply chain measure. Operating in parallel to the Supreme Court case, it is itself a partial legal shield for Bayer’s US operations.
Bayer’s response to the executive order was unambiguous: the company stated it “reinforces the critical need for US farmers to have access to essential, domestically produced crop protection tools such as glyphosate.”
Then, in the Supreme Court case, the Department of Justice — representing the Trump administration — filed a brief siding with Monsanto/Bayer, arguing that federal pesticide law should preempt state-level failure-to-warn claims.
So the sequence looks like this: a company facing nearly $20 billion in cancer settlements and more than 100,000 lawsuits has the White House declaring its product a national security asset, the executive order granting it partial legal immunity under the Defense Production Act, and the Department of Justice arguing before the Supreme Court that future victims should be unable to sue.
It is worth pausing on that for a moment.
What Monsanto v. Durnell Actually Decides — and What It Leaves Unanswered
The Durnell case is not, at its core, about whether glyphosate causes cancer. That question remains genuinely contested in the scientific literature, though the International Agency for Research on Cancer classified it as “probably carcinogenic to humans” in 2015 — a finding that helped trigger the wave of litigation now before the court.
What is being decided is something more fundamental: whether a regulatory approval by a government agency — based on studies submitted by the manufacturer seeking that approval — should permanently shield that manufacturer from accountability to the people it may have harmed.
The justices pressed Monsanto’s lawyers on this directly during oral arguments. What happens, several justices asked, when new science emerges indicating harm that was not apparent when a product was originally approved? If federal preemption applies, the answer appears to be: nothing. The manufacturer is protected. The approval stands. The victims have no recourse.
Observers who attended the hearing described it as too close to call. One analyst predicted a 5-4 or 6-3 decision in favour of Durnell — meaning the current legal protections for plaintiffs survive. Others were less optimistic. The court’s current composition has in recent terms shown a tendency to favour federal regulatory authority over state-level tort claims — a pattern that may advantage Bayer’s preemption argument.
What is clear is that the decision will affect not just the tens of thousands of pending Roundup cases, but the broader legal landscape for pesticide liability across the United States. If Bayer wins, it establishes a precedent: that federal regulatory approval is a get-out-of-jail-free card for chemical manufacturers, regardless of what subsequent science reveals.
The EPA Safety Approval Bayer Wants to Use as a Legal Shield Was Built on Manipulated Science
To understand why this matters, it helps to recall what the regulatory approval process for glyphosate actually involved.
As we have documented in this investigation series, the animal studies used to establish glyphosate’s safety profile were conducted using laboratory rodents whose biology had been profoundly distorted by decades of commercial breeding — producing animals with artificially elongated telomeres, suppressed melatonin systems, and chronic stress physiology that may cause them to systematically underestimate toxic harm. The neurotoxicity testing used to rule out links to conditions like Parkinson’s disease was, according to a 2023 commentary in The Lancet Planetary Health, fundamentally inadequate to detect the kind of slow, progressive neurological damage those conditions involve.
And the internal Monsanto documents released during litigation — the Monsanto Papers — revealed a sustained, deliberate effort to manage the scientific record: ghostwriting studies published under independent academics’ names, attempting to influence regulatory reviewers, and suppressing internal awareness of safety concerns.
This is the evidentiary foundation on which the EPA’s safety determination rests. This is the regulatory approval that Bayer is now asking the Supreme Court to treat as an impenetrable legal shield.
The question is not simply whether glyphosate causes cancer. The question is whether a regulatory process that was systematically manipulated by the manufacturer seeking approval should be allowed to permanently foreclose the legal rights of the people that manufacturer may have harmed.
State Liability Shield Laws, Lobbying, and the Industry’s Multi-Front War to Escape Roundup Accountability
The Supreme Court case is not the only front on which the pesticide industry is seeking protection from accountability.
As the litigation pressure mounted, pesticide manufacturers intensified lobbying campaigns in state legislatures across the US, pushing for what critics call “liability shields” — laws that would prevent state-level lawsuits when products comply with EPA-approved labelling. Georgia and North Dakota have already enacted such protections. Similar proposals are active in other agricultural states.
The pattern is consistent and deliberate: when the courts begin to hold manufacturers accountable, the manufacturers move to change the rules. When juries find that Roundup should have carried a cancer warning, the industry lobbies legislatures to make such findings legally irrelevant. When litigation costs approach $20 billion, the White House is persuaded to declare the product a matter of national defence — and to grant the manufacturer partial immunity in the process.
At each step, the mechanism of accountability — the ability of an ordinary person harmed by a product to seek legal remedy — is narrowed, weakened, or eliminated.
Why the Monsanto v. Durnell Ruling Matters for New Zealand’s Glyphosate Regulation
New Zealand is not subject to US Supreme Court rulings. Our legal system is separate. But the implications of this case extend well beyond American jurisdiction, for a straightforward reason: the regulatory safety assessments that MPI and the EPA New Zealand rely on when approving glyphosate and setting exposure limits are substantially derived from the same international review processes that incorporate — and in some cases defer to — US EPA determinations.
If the US Supreme Court rules that the EPA’s safety determination is legally definitive — sufficient to shield a manufacturer from liability regardless of subsequent evidence of harm — it will entrench the authority of that determination in ways that ripple through international regulatory systems. It will make it harder, not easier, for other regulatory bodies to diverge from the EPA’s position. And it will signal to the global agrichemical industry that the pathway to permanent protection from accountability runs through regulatory capture rather than through science.
For New Zealand, where MPI and the EPA have yet to adequately address the growing body of evidence linking glyphosate to neurological harm — as we documented in our investigation into glyphosate and Parkinson’s disease — this matters. The regulatory framework we rely on is not independent of what happens in Washington. It is downstream of it.
Whatever the Supreme Court Decides: Is Glyphosate Actually Safe?
Whatever the Supreme Court decides in July, there is one question it cannot resolve: whether glyphosate is actually safe at the levels to which New Zealanders — and Americans, and Europeans, and billions of people worldwide — are routinely exposed.
That question remains open. The science is genuinely contested. The regulatory testing framework has significant structural limitations. The neurotoxicity assessment is inadequate. The synergistic effects of glyphosate combined with other environmental exposures have never been properly studied. The gut microbiome disruption pathway that may connect glyphosate exposure to neurological disease has barely been investigated.
What the Supreme Court will decide is something different and, in some ways, more immediately consequential: whether the people harmed by glyphosate — if it is causing harm — retain the legal right to seek accountability from those who manufactured it, sold it, and told them it was safe.
Bayer says they should not. The Trump administration agrees.
John Durnell — and the more than 100,000 people who filed lawsuits like his — disagrees.
The nine justices of the United States Supreme Court will decide whose view prevails. And the rest of the world will be watching.
This article draws on publicly available court documents, regulatory filings, and published news reporting. We encourage readers to consult the primary sources and form their own conclusions.
Further Reading
On Monsanto v. Durnell
- Legal Information Institute, Cornell Law School. Monsanto Company v. Durnell — case summary and documents. law.cornell.edu — Full case background, questions presented, and amicus briefs.
- The New Lede (April 2026). No safe bets — Supreme Court glyphosate case seen too close to call. thenewlede.org — Post-hearing analysis including observer predictions on the outcome.
- Bergeson & Campbell (May 2026). Supreme Court Grapples with Roundup, Federal Preemption, and the Limits of EPA Authority. lawbc.com — Detailed legal analysis of the FIFRA preemption arguments.
- Beyond Pesticides. Monsanto v. Durnell — real-time analysis. beyondpesticides.org — Public interest perspective including audio from the Supreme Court session.
On the Trump executive order
- White House Fact Sheet (February 18, 2026). Promoting the National Defense by Ensuring an Adequate Supply of Elemental Phosphorus and Glyphosate-Based Herbicides. whitehouse.gov — The official White House statement on the executive order.
- Food Safety Magazine (February 2026). Trump Pushes for Greater Production of Controversial Herbicide Glyphosate. food-safety.com — Analysis of the executive order’s implications including MAHA pushback.
On the Monsanto Papers
- US Right to Know. The Monsanto Papers. usrtk.org — Archive of internal documents released during litigation.
Related NMGNZ investigations
- No More Glyphosate NZ. Is Glyphosate Really Safe? Why the Animal Studies Say Less Than You Think. nomoreglyphosate.nz
- No More Glyphosate NZ. Glyphosate and Parkinson’s Disease: Is New Zealand Asking the Right Questions? nomoreglyphosate.nz
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