Clearing the Weeds: The Ninth Circuit Confirms that There is Not (And Never Has Been) a Presumption of Admissibility in Its Case Law Addressing Rule 702

The judge overseeing the In re Roundup Products Liability Litigation MDL once remarked that “When you [consider] Ninth Circuit law, you come away with a pretty strong feeling that the Ninth Circuit is more tolerant of shaky expert opinions than other circuits.”  But that was before the 2023 amendments to Federal Rule of Evidence 702, and appellate courts around the country have gradually been addressing how the amendments impact pre-amendment case law. The Ninth Circuit recently joined the ranks in a way, affirming that same judge’s exclusion of an expert’s causation opinion while harmonizing Ninth Circuit case law with the purposes of the 2023 amendments. The opinion is Engilis v. Monsanto Company, --- F.4th ---, 2025 WL 2315898 (9th Cir. 2025), and the headlines may come as a surprise to some.