IBM sought a refund of federal excise taxes it had paid on insurance premiums covering shipments of exported products. The government argued the tax fell on the insurance service, not the goods. Justice Thomas's opinion took the Export Clause of Article I, § 9 ('No Tax or Duty shall be laid on Articles exported from any State') at face value: a tax on export insurance is functionally a tax on the export itself and is therefore forbidden. The decision reaffirmed the Export Clause as one of the few absolute prohibitions on federal taxing power and continues to constrain federal user fees and excise regimes touching international trade.