In February 2026, the Environmental Protection Agency (EPA) finalized a regulation rescinding the "endangerment finding," which previously determined that greenhouse gas emissions from mobile sources contribute to air pollution endangering public health or welfare. This move, a priority of the Trump Administration, has sparked immediate legal challenges from environmental groups and blue states, who have filed suits contesting the rescission.

Critics argue that the EPA's legal rationale is weak and unlikely to hold up in court. The EPA contends that under the best reading of the Clean Air Act (CAA), Section 202 "does not authorize the Agency to prescribe emission standards in response to global climate change concerns." However, this position conflicts with prior court rulings. Notably, the Supreme Court in Massachusetts v. EPA found that Section 202 clearly authorizes the EPA to regulate greenhouse gas emissions from new motor vehicles if it determines such emissions contribute to climate change.

Chief Justice John Roberts, writing for the majority in Loper Bright, emphasized that this decision does not call into question earlier statutory interpretations affirming the EPA's regulatory authority. This precedent undermines the EPA's current claim that the statute precludes regulation based on global climate change concerns.

Jonathan H. Adler, writing for Reason, describes the EPA's rescission as "a costly, symbolic gesture that will divert administration resources from more meaningful deregulatory initiatives and does nothing to advance a rational climate change policy." He also notes that some legal arguments against the rescission are fanciful, while others are grounded in traditional administrative law.

The unfolding litigation will test whether courts uphold the EPA's rollback or reaffirm the agency's authority to regulate greenhouse gases under existing law.

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