In Massachusetts v. EPA, the Supreme Court legislated from the bench, authorizing and indeed pushing EPA to control emissions of greenhouse gases (GHGs) for climate change purposes. This is a policy decision of immense economic and political magnitude that Congress never intended or approved when it enacted and amended the Clean Air Act (CAA or Act). Regulating GHGs under the CAA leads inexorably to "absurd results," including an economically-chilling administrative quagmire. To prevent GHG regulation from overwhelming agency administrative resources and stifling economic development, EPA proposes to suspend, for six years, the "major" source applicability thresholds for the CAA pre-construction and operating permits programs. That is, EPA proposes to amend the Act. This violation of the separation of powers compounds the constitutional crisis inherent in the Court’s substitution of its will for that of the people’s elected representatives. The small-business protections proposed in the Tailoring Rule are temporary, legally dubious, and incomplete. Even if courts uphold the Tailoring Rule, despite its flouting of clear statutory language, it will not avert the most absurd result of the Court’s misreading of the CAA: regulation of carbon dioxide (CO2) and other greenhouse gases under the National Ambient Air Quality Standards (NAAQS) program. EPA runs enormous political risks leading the charge for GHG regulations not approved by Congress. It is in the Agency’s best interest not to oppose legislative action to overturn the endangerment finding and Mass. v. EPA.