P brought suit against Bidwell (D) to recover a tax paid under protest. P sought to recover the amount of duty paid on merchandise that came into the United States from Puerto Rico after July 1, 1900. The tax was imposed under the federal Foraker Act which also created a government for Puerto Rico. P’s argument for the right to recover is predicated on the assumption that Puerto Rico, by the ratification of the treaty with Spain, became incorporated into the United States, and therefore the act of Congress which imposed the duty in question is repugnant to Article I, sec. 8, clause 1, of the Constitution providing that 'The Congress shall have Power To lay and collect Taxes, Duties, Imposts, and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts, and Excises shall be Uniform throughout the United States.' P contends that the duty collected was also repugnant to the export and preference clauses of the Constitution. The trial court dismissed P’s suit as Puerto Rico was not part of the United States. P appealed.