To a surprising degree, many critical issues pertaining to the foreign affairs law of the United States remain unresolved, even after over 220 years of experience under the Constitution. The distribution of war powers between the President and Congress, limits on the President's power to make, suspend, or terminate obligations under treaties and other international agreements, as well as the proper role of the federal courts in adjudicating foreign relations disputes, all remain open - and highly contested - matters in contemporary legal discourse. Perhaps the most contentious issue in current debates is also the most fundamental: the very status of customary international law as part of the law of the United States. The question of whether customary international law (CIL) is a species of federal law, state law, or something in between has spawned a lively polemic, extending well beyond the ruminations of academics to the central corridors of power in this country.

As with much constitutional discourse, we continue to re-live arguments of great historical pedigree and salience. But something confounds the current conversation as to the status of CIL in U.S. courts: The noted absence of any sustained consideration of the relevance and applicability of principles concerning the general maritime law (GML) - that body of non-statutory, non-treaty, and judge-made law that governs the substantive obligations and procedural remedies of seafarers and those involved in maritime commerce. This contribution attempts to rectify that omission and rediscover the now largely forgotten set of connections between CIL and the GML. Although it will require resurrecting fragments of doctrinal history, this is no mere antiquarian exercise - it is the legal historian's equivalent of an archaeologist conducting a dig at a long-lost ruin. Indeed, for reasons that will become readily apparent, the fruits of this excavation have a startling consequence: a simple, elegant, and historically valid solution to the question of whether CIL is part of the "law of the land" of the United States.

My thesis here is straightforward enough: CIL should be accorded the same status as the GML in the United States - no more, and no less. Crucial to this conclusion is linking the doctrinal and intellectual history of the GML with the key observation that its status as the "law of the land" is not an all-or-nothing, "binary" proposition. And, indeed, the GML has been regarded as federal law for some purposes, but not for others. Specifically, the judge-made GML is considered "supreme" within the meaning of the Constitution's Article VI as the "law of the land;" preempts contrary state law (both decisional and statutory) that conflicts with its essential attributes and demand for uniformity; permits the Supreme Court to review state court decisions involving GML matters when such cases are brought in state court under the "savings to suitors" clause; but does not allow matters arising under the GML to be automatically characterized as federal questions for the purposes of that source of jurisdiction, absent some other basis of jurisdiction (such as a cause of action based on a treaty or statute). I argue here that CIL should have precisely the same attributes of the "law of the land" as the GML.

Although federal judges have widely dismissed both foreign relations law and maritime law as "exceptional" categories, or enclaves, of law-making, analogies of GML to CIL are rejected because admiralty is viewed as a legal realm that is - because of historical and practical considerations - weird and different. But the historical and intellectual links between the two domains remain under-theorized and not well understood. This piece attempts to demystify these assertions of exceptionalism and provide a coherent, chronological account of the doctrinal unity of GML and CIL, focusing on the main currents of doctrinal change in the status of CIL and GML as law in the United States. After examining in Part I the role and function of CIL and GML in the early years of the Republic (up to the Civil War), I devote substantial attention in Part II to the period between 1860 and 1900, where arguably the greatest transformation occurred in judicial characterizations of these subjects as they each reached their apogee in judicial recognition and both CIL and GML were reconciled. Part III considers the period from 1900 to 1959, the time when the happy marriage between CIL and GML was irretrievably broken because of unreconciled differences, largely attributable to the Supreme Court's rulings in two cases: Southern Pacific Co. v. Jensen and Erie Railroad Co. v. Tompkins. These two decisions contributed to the dilemma we face today in reconciling the jurisprudential bases of GML and CIL as law in the United States. Part IV explores the contemporary debate about the status of CIL, particularly as reflected through the Supreme Court's discussions in such cases as Banco Nacional de Cuba v. Sabbatino and Sosa v. Alvarez-Machain. I conclude by offering a possible way forward in achieving the full doctrinal rapprochement between CIL and GML as the "law of the land."