William J. Brennan, Jr., McKesson Corporation v. Division of Alcoholic Beverages and Tobacco Department of Business Regulation of Florida…
“ The question before us is whether prospective relief, by itself, exhausts the requirements of federal law. The answer is no: If a State places a taxpayer under duress promptly to pay a tax when due and relegates him to a postpayment refund action in which he can challenge the tax's legality, the Due Process Clause of the Fourteenth Amendment [14] obligates the State to provide meaningful backward-looking relief to rectify any unconstitutional deprivation. ”
