In a term with multiple major cases addressing the shape and scope of the administrative state, the Court’s emergency docket ruling in Ohio v. Environmental Protection Agency temporarily pausing a not-yet-fully-implemented environmental rule may seem technical and less consequential. The majority’s approach, however, reinforces a template for pausing regulations prior to full judicial review. It also underlines the trend of assigning more power to the courts to manage and calibrate administrative regulation. This chapter provides some background on the Clean Air Act and describes how the EPAEnvironmental Protection Agency (EPA) works with states to meet air quality standards. It then turns to the details and implications of this dispute.