A group of leading academics who helped write the U.S. federal judiciary’s Reference Manual on Scientific Evidence is criticizing court officials for removing a chapter on climate science from the manual’s newest edition, warning that the decision politicizes a tool meant to help judges evaluate complex scientific testimony. 28 co-authors of the manual’s fourth edition signed an open letter calling the deletion “troubling” and arguing it reflects capitulation to partisan pressure rather than a neutral editorial judgment about scientific quality.
The Reference Manual is influential in U.S. courts because it is designed to give judges a reliable, peer-reviewed foundation for assessing expert evidence in technical disputes—exactly the kind of disputes that arise in mass-tort cases, public-health litigation, and climate-related lawsuits. The co-authors emphasized that the manual’s value depends on its perceived independence and objectivity, and they argued that allowing political actors to veto specific scientific content undermines judicial decision-making. Allegedly, the manual has been cited by more than 1,300 judges since it first appeared in 1994, illustrating how widely it is used.
The controversy began after 27 Republican state attorneys general, led by West Virginia Attorney General JB McCuskey, pressured the Federal Judicial Center (FJC)—the judiciary’s research and education arm—to remove the climate chapter. In their January 29 letter, they argued the chapter “places the judiciary firmly on one side” of disputed issues in climate litigation, especially questions about climate “attribution” (linking specific harms to greenhouse-gas-driven climate change). These Republican-led states have opposed lawsuits by Democratic-led states and local governments accusing oil and gas companies of misleading the public about climate change.
The FJC told the attorneys general on February 6 that it would omit the chapter from the updated manual (released in December), and the FJC later declined to comment publicly on the criticism. The open-letter writers—drawn from institutions including Columbia, Stanford, UC Berkeley, and the University of Pennsylvania—argued that removing the chapter deprives judges of a “carefully reviewed baseline explanation” of the relevant science at a moment when climate evidence is increasingly central to courtroom battles.
The chapter at issue was co-authored by Jessica Wentz and Radley Horton of Columbia Law School, and it was intended as practical guidance for judges navigating a fast-growing body of climate-related expert testimony. Critics of the removal say the goal was not to steer case outcomes, but to ensure courts can evaluate the scientific record consistently and competently—especially when litigants present dueling experts and methodological claims.
Political blowback is spreading beyond academia. 16 Democratic lawmakers, led by Senator Ron Wyden, also demanded the chapter be reinstated, warning that “censorship of scientific information” undercuts the judiciary’s nonpartisan role and weakens the quality of legal decision-making on science-heavy issues.
In short, the dispute is not only about a single chapter—it’s about whether the courts’ scientific reference materials remain insulated from partisan conflict, or become another front in the broader political war over climate litigation and accountability.
