EPA rests the rescission on three grounds it calls severable, a reading of Clean Air Act section 202(a)(1), the major questions doctrine and a finding that vehicle standards cannot materially affect the danger. It does not answer the climate science and health comments on their merits.
The rule survives if the D.C. Circuit upholds any one ground. The science record reaches the futility ground, which rests on climate models EPA assumed valid. Whether setting the science and health comments aside met the duty to respond is for the court to decide.
On the merits. Whether greenhouse gases fall within section 202(a), what Massachusetts v. EPA decided, futility, use of AI.
By a legal ground. Backstop standards, reliance by automakers and states, tribal treaty rights.
Out of scope. Climate science and the Energy Department report, public health, federal preemption.
No response. About 1,530 diesel owners' complaints on DEF, particulate filters and EGR, equipment EPA did not propose to change.
The rule falls only if the court rejects all three grounds. Review with counsel the futility analysis in preamble section V.C and the out of scope list in sections 3.1, 5.11 and 7.1.
EPA set no backstop standards and took no action on preemption. Two district courts have held the rescission does not change their preemption analysis.
Comments on EPA-HQ-OAR-2025-0124 closed November 2, 2026. That proposal uses the same local or regional reading and adds a futility model, so check whether the final rule answers the modeling comments.
EPA's response lists the campaign letters in Appendix A and does not engage their arguments. Detailed comments on the adopted legal grounds reach the part of the record EPA answers at length.
A merits briefing schedule in American Public Health Association v. EPA, D.C. Cir. No. 26-1037; the court denied a stay on October 5, 2026.
EPA's decisions on four petitions for reconsideration, and the final power plant rule in EPA-HQ-OAR-2025-0124.