On December 20, 2023, the Supreme Court of the United States agreed to hear oral argument in four consolidated cases:

Ohio, et al. v. EPA, et al.; Kinder Morgan, Inc., et al. v. EPA, et al.; American Forest & Paper Association, et al. v. EPA, et al.; U.S. Steel Corporation v. EPA, et al., Nos. 23A349, 23A350, 23A351, 23A384: These consolidated cases address challenges to the Environmental Protection Agency’s Good Neighbor Plan to reduce cross-state air pollution. The cases were originally presented to the Court as emergency motions requesting a stay of the Plan’s implementation pending resolution of the various procedural and substantive challenges to the Plan under consideration in the D.C. Circuit. The Court scheduled oral argument for the cases in its February sitting and directed the parties to address, among other issues, whether the emissions controls imposed by the Plan are reasonable regardless of the number of States subject to the Plan.