Did the Seventh Circuit err under the exception to the comity doctrine by holding Illinois state court remedies 'adequate' and 'complete' even though Illinois courts bar the equitable jurisdiction legally required to consider claims for prospective declaratory relief under 28 U.S.C. § 2201?

QUESTION PRESENTED The Court has previously stated an exception to the comity doctrine: local taxpayers with Equal Protection Clause property tax claims are remitted to their state court remedies, but only “if their federal rights will not thereby be lost.” Fair Assessment in Real Estate Ass’n, Inc. v. McNary, 454 U.S. 100, 116 n.8 (1981). Comity applies when state court remedies are “plain, adequate, and complete.” Jd. at 116. Under 28 U.S.C. § 2201, petitioners have a federal right to claim prospective declaratory relief for Equal Protection Clause violations challenging Illinois property-tax assessments in future years. But, Illinois has a “well-established proposition that under Illinois law, equitable jurisdiction is not available for property tax relief when there is an adequate remedy of law.” Perry v. Coles County, 906 F.3d 583, 589 (7th Cir. 2018). So, when the Seventh Circuit affirmed the district court’s dismissal of petitioners’ claims, petitioners lost their federal right to claim prospective declaratory relief under § 2201 because petitioners were unable to obtain that relief from either state or federal court. See id. at 589-90. Did the Seventh Circuit err under the exception to the comity doctrine by holding Illinois state court remedies “adequate” and “complete” even though Illinois courts bar the equitable jurisdiction legally required to consider claims for prospective declaratory relief under 28 U.S.C. § 2201?