The court of appeals erred in allowing respondents to maintain their suit for recovery of taxes under the Export Clause without having filed a timely administrative claim for refund. The Internal Revenue Code plainly states that "[n]o suit or proceeding" to recover "any" tax "alleged to have been erroneously or illegally assessed or collected" may be brought "in any court" unless the taxpayer first files a timely refund claim and allows the Secretary of the Treasury a specified time to resolve it. 26 U.S.C. 7422(a); see 26 U.S.C. 6511(a) and (b)(1), 6532(a). That detailed and finely reticulated tax- refund scheme, including the mandatory administrative claims process and the firm, non-tollable limitation period, cannot be circumvented by the expedient of pleading a constitutional claim and asserting jurisdiction under the Tucker Act. Claims for repayment of unlawful tax are subject to the exclusive procedural requirements set out in the tax code, no matter what the source of the alleged illegality-be it regulatory, statutory, or constitutional.