Arcelormittal v. Ak Steel Corporation

“If a dispute is not a proper case or controversy” under Article III of the Constitution, we “have no business deciding it.” DaimlerChrysler Corp. v. Cuno, 547 U.S. 332, 341, 126 S.Ct. 1854, 164 L.Ed.2d 589 (2006). Indeed, “[n]o principle is more fundamental to the judiciary’s proper role in our system of government.” Simon v. E. Ky. Welfare Rights Org., 426 U.S. 26, 37, 96 S.Ct. 1917, 48 L.Ed.2d 450 (1976); see Valley Forge Christian Coll. v. Ams. United for Separation of Church & State, Inc., 454 U.S. 464, 471, 102 S.Ct. 752, 70 L.Ed.2d 700 (1982) (describing the case or controversy check…