Trump Orders Review of Climate Guidance Used by Federal Judges
WASHINGTON: President Donald Trump has directed federal officials to review the development and use of climate science guidance that was included in a reference manual for federal judges, arguing that the material reflected political bias rather than objective science.
In a post on Truth Social on June 19, Trump criticized the climate chapter of the Reference Manual on Scientific Evidence, describing it as "politically driven" and based on "discredited science." He noted that the chapter had already been withdrawn earlier this year by the U.S. federal judiciary following objections from Republican state attorneys general.
The Reference Manual on Scientific Evidence is produced by the Federal Judicial Center—the research and education arm of the federal judiciary—in partnership with the National Academies of Sciences, Engineering, and Medicine. Its fourth edition was published in December 2025.
Although the manual is not legally binding, it serves as a resource to help federal judges evaluate complex scientific and technical evidence presented in court.
Trump said federal judges should rely on objective scientific evidence rather than what he described as politically influenced guidance. He also stated that federal suspension and debarment officials would review the manual for potential political bias, adding that taxpayers should not fund what he called "climate fraud."
Climate Chapter Removed After Republican Challenge
The judiciary removed the chapter titled "Reference Guide on Climate Science" in February after 27 Republican attorneys general formally challenged its content.
In a Jan. 29 letter led by West Virginia Attorney General JB McCuskey, the attorneys general argued that the chapter failed to present an independent and impartial assessment of climate science. They claimed it endorsed only one scientific perspective while excluding competing views on climate-related issues that are frequently debated in court.
The group criticized the chapter's authors, Jessica Wentz and Radley Horton, for relying primarily on experts associated with the United Nations' Intergovernmental Panel on Climate Change (IPCC) while not consulting specialists from the U.S. Department of Energy.
According to the attorneys general, presenting one scientific interpretation as settled could influence judicial decisions on disputed legal matters involving climate science. They warned that if such an approach were accepted in climate litigation, it could establish a precedent for similar treatment of scientific evidence in cases involving pharmaceuticals, election law, or Second Amendment issues.
The letter also questioned the chapter's methodology and suggested that the authors' involvement in climate-related legal advocacy could undermine perceptions of neutrality.
Trump echoed those concerns, claiming the guidance had influenced major climate-related court cases and contributed to costly legal outcomes across the country.
Authors Defend the Guidance
Following the withdrawal of the chapter, Wentz and Horton submitted a letter to the federal judiciary defending their work.
They said the chapter identified only one point as scientifically settled—that human activity is the primary cause of modern climate change. They emphasized that the guide acknowledged varying degrees of scientific uncertainty regarding the detection, attribution, and projection of specific climate impacts.
The authors also stated that the chapter did not claim that any particular weather event or alleged harm in a lawsuit could be definitively attributed to climate change. Instead, they said its purpose was to explain scientific methods, evidence, uncertainties, and limitations so judges could better understand expert testimony.
In the manual's foreword, Supreme Court Justice Elena Kagan described the publication as a practical resource designed to help judges evaluate scientific and technical evidence while recognizing both its strengths and limitations. She wrote that the manual aims to improve the quality of judicial decision-making by promoting a better understanding of scientific principles rather than advocating particular legal outcomes.
The National Academy of Sciences had not publicly responded to Trump's announcement of the review at the time of reporting.