THE SHIELD | PART TWO OF FOUR

Seven to Two

What the Supreme Court actually decided, what the dissent actually found, and why the difference matters more than the headline.

In Part One of this series, we traced how Bayer and Monsanto shifted their defence of Roundup from a scientific argument to a legal one. The question was no longer whether glyphosate causes cancer. The question was whether anyone should be allowed to argue that in court. On June 25, 2026, the United States Supreme Court answered seven to two.

Before drawing conclusions from that number, it is worth reading what the Court actually said, and what it carefully did not say.

The Man at the Centre

Edwin Durnell is a Missouri man. He was diagnosed with non-Hodgkin’s lymphoma and believed Roundup was responsible. He sued Monsanto on the grounds that the company had failed to warn him about the cancer risk. A Missouri jury heard the evidence and agreed. They awarded him $1.25 million.

Monsanto appealed. The argument was not that Durnell was wrong about the cancer. The argument was that the question should never have reached a jury in the first place. Because the Environmental Protection Agency had approved Roundup’s label under federal pesticide law, Monsanto contended that state courts had no authority to second-guess whether that label was adequate.

That argument made it to the United States Supreme Court. And it won.

Justice Brett Kavanaugh wrote the majority opinion, joined by Chief Justice Roberts and Justices Alito, Sotomayor, Kagan, Barrett, and Thomas. That lineup is the first thing to understand. This was not a conservative court protecting corporate interests over liberal dissent. Sotomayor and Kagan, the Court’s two most reliably progressive voices, signed onto Kavanaugh’s reasoning. Bayer got exactly what it needed: not a partisan win vulnerable to accusations of purchased influence, but a structural legal argument that crossed ideological lines and arrived wearing the clothing of consensus.

The majority’s holding is precise and worth stating exactly. The Federal Insecticide, Fungicide, and Rodenticide Act, known as FIFRA, preempts state-law failure-to-warn claims when those claims would require a manufacturer to add a warning the EPA has not required on the approved label. Because the EPA has never required a cancer warning on Roundup’s label, Durnell’s claim that Monsanto should have included one is, in the majority’s view, a state-law requirement that FIFRA explicitly prohibits.

The majority was equally explicit about what it was not holding. The Court did not declare glyphosate safe. It did not find Roundup’s label scientifically adequate. It did not resolve whether glyphosate causes cancer. The scientific question was deliberately left open. The courtroom door was closed regardless.

How the Door Gets Closed

To understand why seven justices reached this conclusion, you need to understand the specific text they were working with. FIFRA contains what the majority calls a uniformity clause. It states that states may not impose any requirements for labelling or packaging “in addition to or different from” those required under the federal statute.

In plain terms: if the federal government has approved what goes on a pesticide label, states cannot use their courts to force something different onto that label. The question is whether a jury verdict demanding a cancer warning constitutes exactly that kind of forbidden state-imposed requirement. Kavanaugh said yes.

He relied on two prior Supreme Court decisions to get there. The first, Bates v. Dow Agrosciences, established that state tort duties count as labelling requirements for FIFRA purposes. The second, Riegel v. Medtronic, applied nearly identical logic to medical devices, holding that FDA approval shields manufacturers from state tort claims that would impose different safety requirements. The pattern across both cases is the same: federal approval as a ceiling, not a floor.

Durnell’s lawyers argued that his claim only required Monsanto to provide an adequate warning, which is all FIFRA requires anyway. Kavanaugh rejected that framing as too general. The specific thing being demanded, a cancer warning, is not what FIFRA requires. It is, in the majority’s view, precisely the kind of additional requirement the uniformity clause was designed to prevent.

The entire structure rests on one factual foundation: the EPA has not required a cancer warning on Roundup’s label because the EPA has determined that glyphosate is not likely to be carcinogenic to humans.

That determination is the load-bearing wall of the ruling. Remove it, and everything collapses. We will return to it in Part Three.

What Two Justices Found

Justice Ketanji Brown Jackson dissented, joined by Justice Neil Gorsuch. Their dissent is not a close call on a genuinely difficult legal question. It is a documented catalogue of what the majority chose not to address.

Start with the history of Roundup’s label itself. In 1999, the EPA approved a Roundup label that did not include a warning about leak risk. The EPA later determined that same approved label failed to meet FIFRA’s own requirements, because the product could spray onto users. The agency imposed civil penalties on Monsanto for distributing a misbranded pesticide under a label the EPA had previously signed off on.

That is not a hypothetical. It is regulatory history with a paper trail. EPA approval did not, in that instance, mean the label was adequate. The agency said so itself, in writing, and made Monsanto pay for it. Jackson’s question follows directly: if EPA approval does not guarantee adequacy even by the EPA’s own subsequent judgment, how can it function as a permanent shield against state courts asking the same question?

Her second finding cuts deeper.

The majority’s preemption argument depends on a specific premise: that Monsanto could not have added a cancer warning to Roundup’s label without EPA pre-approval. If Monsanto had no practical way to add the warning, then a state tort duty requiring it becomes an impossible demand, and impossible demands are preempted. That is the logic.

Jackson documents that the premise is false.

Federal regulations permit pesticide manufacturers to make certain changes to approved labels without prior EPA approval, through a process called minor modification notification. The manufacturer notifies the agency, makes the change, and the updated label takes effect. Jackson identifies at least six instances in which manufacturers used exactly this process to add Proposition 65 cancer warnings to pesticide labels, with no prior EPA approval sought or required.

One of those six instances involves a Bayer subsidiary.

In 2012, Bayer CropScience used the minor modification process to add a cancer warning to the label of LARVIN Technical, an insecticide. The submission cited the same federal regulation Jackson’s dissent relies on. The EPA’s response letter confirmed the notification was accepted. No prior approval was required or sought. This is a different product and a different chemical from Roundup, but the regulatory mechanism is identical, the parent company is the same, and the process Monsanto told the Supreme Court was unavailable is a process Bayer had already used twelve years earlier.

Jackson also raised a procedural problem the majority chose not to engage with. Monsanto never asked for a jury instruction tying the trial verdict to FIFRA’s specific misbranding standard. It never argued at trial that the evidence was insufficient under that narrower framework. The majority therefore ruled on a preemption question the trial record never properly raised. Six justices closed a courthouse door using a key that was not tested at the door.

None of this made it into the majority opinion. The Bayer subsidiary cancer warning document went unaddressed. The 1999 leak-warning penalty went unaddressed. The procedural forfeiture went unaddressed. Six justices said nothing about any of it.

The Odd Concurrence

Justice Clarence Thomas joined the majority but wrote separately, and what he wrote was strange. He did not celebrate the outcome. He questioned the constitutional foundation it rests on.

Thomas argued that FIFRA itself may exceed Congress’s Commerce Clause authority, and that EPA’s regulatory scheme amounts to an unconstitutional delegation of legislative power that benefits incumbent companies at the expense of smaller competitors and consumers. He used Bayer’s legal victory as a platform to attack the architecture that made the victory possible.

For now it is a solo concurrence with no majority behind it. But if Thomas’s view ever commands five votes, the preemption clause Bayer just won on becomes constitutionally suspect. The shield could be dismantled at its foundation by the same ideological movement that helped construct it. Worth watching.

The Question That Remains

Edwin Durnell lost. More than 100,000 other plaintiffs lost the clearest path to their day in court. The ruling did not say glyphosate is safe. It said the agency responsible for deciding that question had already weighed in, and that federal law does not permit state juries to reach a different conclusion through tort litigation.

Everything flows from that EPA determination. It is why the label has no cancer warning. It is why the state claims are preempted. It is the factual predicate the entire seven-to-two ruling stands on.

In Part Three of this series, we examine what that determination is actually worth, and what a federal appeals court already found when it looked closely at how the EPA arrived at it.

The answer was not reassuring. And nobody fixed it before it became the foundation of a Supreme Court ruling.

Editor’s Notes

Primary sources for this piece: Monsanto Co. v. Durnell, U.S. Supreme Court, decided June 25, 2026 (majority opinion by Kavanaugh, J.; concurrence by Thomas, J.; dissent by Jackson, J., joined by Gorsuch, J.); EPA notification record for LARVIN Technical, EPA Reg. No. 264-343, Bayer CropScience, 2012 (confirming minor modification cancer warning via 40 CFR 152.46); Natural Resources Defense Council v. U.S. Environmental Protection Agency, 38 F.4th 34 (9th Cir. 2022).

Confidence tier: All factual claims in this piece are verified against named primary sources. The LARVIN Technical finding is drawn from the EPA notification record itself, not from secondary reporting. The 1999 leak-warning penalty is cited in Jackson’s dissent. The LARVIN product is a different chemical from glyphosate and is noted as such in the text. No claims in this piece are inferred or alleged; they are documented.

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