Legal Scholars Assess State Climate Authority After Endangerment Repeal; California Formally Sues EPA

By February 23, a week after the EPA’s final rule was published, a detailed legal landscape had emerged around the endangerment finding repeal. Legal Planet, a UC Berkeley/UCLA environmental law publication, published a landmark analysis of what state regulatory authority remained after the federal abandonment. The analysis concluded that states retained substantial power: eliminating the federal endangerment finding had no effect on state authority over stationary sources like power plants, leaving California’s cap-and-trade program and similar state-level schemes legally unaffected. For vehicle emissions, the analysis found the impact was actually potentially favorable for states - removing the federal basis could paradoxically strengthen California’s independent authority to set its own vehicle emissions standards under Clean Air Act waiver provisions.

Harvard’s Salata Institute published a parallel analysis of the EPA’s legal reasoning for the rescission, finding it legally unprecedented and unlikely to survive the “arbitrary and capricious” review standard of the Administrative Procedure Act. The core problem: Massachusetts v. EPA (2007) remains binding Supreme Court precedent holding that greenhouse gases are air pollutants requiring EPA regulation. The Trump EPA’s legal theory required arguing it could simply ignore a Supreme Court ruling without overturning it - a position that legal scholars across the political spectrum described as constitutionally untenable.

California formally filed suit in the D.C. Circuit on or around February 23, joining the multistate legal fight. Attorney General Rob Bonta framed the challenge as a defense of “well-settled law” against what he characterized as politically-motivated scientific denialism serving fossil fuel industry interests. Massachusetts, Connecticut, and other coalition members were coordinating separate state filings. Cities and municipalities announced they were also preparing legal challenges, creating the prospect of dozens of simultaneous cases that courts would need to consolidate. The repeal thus produced an immediate paradox: by eliminating federal authority, it may have strengthened the legal position of state regulators and plaintiffs suing fossil fuel companies, since the EPA’s long-held scientific conclusions were no longer available to fossil fuel defendants as a shield against private liability claims.