6 It is a fundamental principle of law that an appellate court does not act on evidence that was not before the lower court(s). See, e.g., Rosewell v La Salle Nat’l Bank, 450 U.S. 503, 518 n.22 (1981). See also VirtualAgility Inc. v. Salesforce.com, 759 F.3d 1307, 1312 (Fed. Cir. 2014); Sky Techs.
Thus, the Court concluded that this case triggered the concerns about litigation in federal court to obstruct the collection of state taxes.Next, the Court addressed whether there was a remedy in state court for the claims asserted in this case that is “plain, adequate, and complete” for purposes of comity”—an identical standard the Supreme Court explained in Fair Assessment in Real Estate Ass’n, Inc. v. McNary, 454 U.S. 100, 116 (1981). Rosewell v. LaSalle Nat’l Bank, 450 U.S. 503, 518 (1981) explained that a state has furnished a plain, speedy, and efficient remedy where “a full hearing and judicial determination of the controversy is assured.” Applying the Rosewell standard, the Court found that Whitwell had a state remedy, in the form of an action in the Madison County circuit court (where this case originally was filed), that was certain and thus plain.