Whitney and other importers brought suit to recover customs duties paid under protest on sugar and molasses imported from the Dominican Republic (then commonly referred to as San Domingo) and entered at the Port of New York. The Collector of Customs, William H. Robertson, assessed duties pursuant to the Tariff Act of March 3, 1883, which imposed duties on sugar generally while recognizing particular treaty-based exceptions (such as the reciprocity arrangement with the Kingdom of Hawaii under which Hawaiian sugar entered free of duty). The importers relied on a prior U.S.–Dominican Republic treaty of amity and commerce (1867), which contained an MFN-style nondiscrimination clause providing that no higher or other duties would be imposed on the products of one party than on like products of any other foreign country. They contended that, because the United States admitted Hawaiian sugar duty-free under a separate reciprocity treaty, the MFN clause obligated equal treatment for Dominican sugar. The government maintained that the 1883 statute governed domestically and that the Dominican MFN clause did not extend to special privileges granted to Hawaii in exchange for reciprocal concessions. The lower court ruled for the Collector, and the importers appealed to the Supreme Court.
When a prior treaty contains a general MFN nondiscrimination clause, does that clause entitle imports from the treaty partner to special tariff concessions later granted to a different country by separate reciprocal agreement; and, if a treaty and a subsequent statute conflict, which governs as domestic law?
Treaties and federal statutes are of equal dignity under the Supremacy Clause. Courts will endeavor to construe them to give effect to both; but if they are irreconcilable, the later-in-time instrument controls as domestic law. Moreover, a general MFN or nondiscrimination clause promising that no higher or other duties will be imposed than those imposed on like products of other nations does not, absent clear language, entitle a treaty partner to special concessions the United States grants a third country as part of a reciprocal arrangement for equivalent consideration. Any resulting breach of an international obligation is for the political branches to address, not for courts to remedy by disregarding a later statute.
The Supreme Court affirmed judgment for the Collector. The Dominican Republic MFN clause did not confer a right to the duty-free treatment the United States afforded Hawaiian sugar under a special reciprocity treaty; and even if the treaty could be read to suggest such parity, the later Tariff Act controlled domestically over any inconsistent treaty provision.
1) Equal status and last-in-time rule: The Court reiterated that both treaties and statutes are the supreme law of the land and neither is inherently superior. Where possible, courts should harmonize them. If not possible, the later expression of sovereign will prevails in domestic courts. Thus, even assuming a treaty might suggest preferential or equal treatment, Congress can alter or supersede those obligations by subsequent legislation setting different rules for customs duties. Courts must apply the statute as written; any grievance that the United States has violated a treaty is a matter for the political branches and international diplomacy. 2) Limits of MFN clauses: Turning to the MFN argument, the Court reasoned that a general promise to impose "no higher or other duties" than those levied on like imports from any other country assures nondiscriminatory baseline treatment, but it does not compel the United States to extend to a treaty partner special benefits that were granted to another country in return for reciprocal concessions. The duty-free entry of Hawaiian sugar arose from a negotiated reciprocity treaty under which the United States received specific, bargained-for benefits; such conditional preferences are not encompassed by a generic MFN clause absent unmistakable treaty language to that effect. Extending those negotiated concessions unilaterally to third countries would undermine the reciprocal bargain and impede Congress's power to regulate foreign commerce. 3) Application to the Tariff Act of 1883: The Act imposed duties on sugar generally while acknowledging specific treaty-based exceptions (e.g., the Hawaiian arrangement). This statutory scheme reflected Congress's intent to preserve certain negotiated preferences while otherwise maintaining duties. Even if the Dominican treaty could be read broadly, the 1883 Act was the later-in-time domestic law and controlled. Therefore, the Collector properly assessed duties on Dominican sugar and molasses, and the importers were not entitled to refunds.
Whitney v. Robertson is a staple for understanding how courts mediate conflicts between international agreements and domestic statutes. It cements the last-in-time rule, frequently cited alongside the Head Money Cases and later decisions such as the Chinese Exclusion Case and Breard v. Greene. For trade and international law, it underscores that MFN clauses—unless specifically drafted—do not automatically import special concessions granted by reciprocity agreements to third countries. For separation of powers and statutory interpretation, Whitney teaches that courts will strive to harmonize treaties and statutes but, failing that, will apply the most recent statute and leave any international fallout to the political branches.
Whitney v. Robertson anchors two enduring principles in U.S. law: the domestic primacy of the latest enactment when a treaty and statute irreconcilably conflict, and the limited reach of MFN clauses that do not expressly extend to special concessions negotiated with third states. By doing so, it affirms Congress's constitutional authority to regulate foreign commerce and delineates the judiciary's constrained role when domestic statutes and international commitments collide.