Will Loper Bright Play a Role in Upcoming Supreme Court Preemption Dispute?

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| April 22, 2026

united states supreme court

The Supreme Court will hear oral argument next week in Monsanto Company v. Durnell. The question presented is “[w]hether the Federal Insecticide, Fungicide, and Rodenticide Act [(“FIFRA”)] preempts a label-based failure-to warn claim where EPA has not required the warning.” Neither party cited Loper Bright in their cert-stage briefing. Nor did the Missouri state-court decisions below, which is perhaps unsurprising. But as Professor Josh Blackman flagged in Reason today, the respondent’s merits brief does cite Loper Bright in arguing against preemption.

Durnell’s brief cites Loper Bright extensively. For example, it states that, “[u]nder Loper Bright, it is for courts to determine the meaning of FIFRA’s provisions absent an express delegation of interpretive authority to the agency.” Elsewhere, the brief argues that, “[a]fter Loper Bright, Monsanto must point to text that expressly vests EPA with authority to render conclusive pronouncements on the meaning of FIFRA’s misbranding provisions and their application to particular pesticides.”  

Monsanto countered in its reply: “Absent an express delegation of authority to bind the judiciary, which neither FIFRA nor any other statute includes, Durnell insists that juries are free to require warnings in addition to or different from those required by EPA in the registration process. There are ample reasons this theory escaped Durnell and everyone else below. It draws no support from Loper and is flatly inconsistent with the text of §136v(b) and Congress’ stated intent to ensure ‘uniformity’ in labeling.”

No matter how the Court resolves this case, it will be interesting to see whether Loper Bright comes up at oral argument and whether, if at all, it will factor into the Court’s analysis.

Michael Pepson is regulatory counsel at Americans for Prosperity Foundation.