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This is the second installment in a three-part series
International law has had a challenging few months. On the one hand, Donald Trump famously declared, “I don’t need international law” and “my own morality [is] the only thing that can stop me.” Kremlin spokesman, Mr. Dmitry Peskov, agreed: “I don’t even understand how anyone can be called upon to follow the norms and principles of international law. It effectively no longer exists.” Or, in Chancellor Friedrich Merz’s words, “[c]lassifications under international law will have relatively little effect.” On a more academic plane, American revisionist scholars foreshadowed these conclusions, announcing more than a decade ago that international law wasn’t U.S. law and that, as a matter of state or foreign law, it either mostly (or always) didn’t exist and wouldn’t be applied by American courts.1
These characterizations of international law, and the role of international law in the United States, have been widely criticized in recent months as contrary to the Nation’s contemporary interests. That is true, but it is not all.
In an earlier NLR article, as well as in my recent book International Law in American Courts, I outlined the American Framers’ view of the role and status of international law in the United States: far from regarding international law as non-existent, unimportant or inapplicable to the Nation, the Framers regarded international law – known in the late-eighteenth century as the “law of nations” – as vitally important to the security, prosperity, and honor of the United States. Consistent with that view, they ensured that the Constitution made rules of international law part of the “Laws of the United States” for purposes of Articles III and VI of the Constitution, directly applicable with preemptive effects in American courts.
These conclusions bear directly on the legitimacy and staying power of claims that international law doesn’t exist or isn’t important: it does exist, it is important, and it will endure in the United States, as it has for the past 250 years. International Law in American Courts explains, from a historical perspective, that this is so.
The Framers’ Early Views
Even before the American Revolution and Constitutional Convention, early American statesmen and authors almost uniformly emphasized both the exceptional character of the law of nations and the vital importance of U.S. compliance with the law of nations in the same manner as treaties. In the words of one commentator, “[a]t our beginning the law of nations played a considerable role. No group of America’s leaders has ever been more mindful of the discipline than were the Founding Fathers.”2
During the pre-Revolutionary period, the American colonists repeatedly invoked the law of nations as the justification for their claim to independence and, later, as the source of the United States’ new rights as a sovereign nation. In the Declaration of Independence, Congress relied prominently on the law of nations, claiming, in what was literally the first act of the newly-sovereign United States, the right to “assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature’s God entitle them,” including, as the law of nations provided, “full Power to levy War, conclude Peace, contract Alliances, establish Commerce, and to do all other Acts and Things which Independent States may of right do.”3 That attention to, and reliance upon, the law of nations continued throughout the Nation’s early decades, with the United States’ rights and duties under international law, and its effective participation in the international legal system, ranking among the Framers’ chief concerns.
During the same pre-1787 era, American courts treated the law of nations as part of the “law of the land,” or “part of our law,” in accordance with well-settled common law doctrine, while also treating rules of the law of nations, like U.S. treaties, as national in character, with preemptive effects on inconsistent state law. That was the case with the Nation’s first federal court—the often-neglected Federal Court of Appeals for Captures, established in 1780 with authority under the Articles of Confederation to review and set aside state court decisions involving application of the law of nations and U.S. treaties in prize cases and related proceedings.4 That Court, whose members included many of those who would shortly become leading Framers (among others, Wilson, Madison, Hamilton, Ellsworth, Randolph, Chase, Pinckney, Dickinson, Adams and Sherman), routinely gave direct application to customary international law rules (and treaty provisions) as matters of national law, specifically for the purpose of overriding contrary state court decisions and contrary state laws which gave insufficient weight to rules of international law.
Similarly, the Continental Congress, also including statesmen who would go on to become both Federalists and Anti-Federalists, repeatedly and expressly addressed the status of the law of nations under the Articles of Confederation. In numerous resolutions, often (and unusually) unanimously adopted, the Continental Congress declared both that diligent compliance with the law of nations was essential to the Nation’s survival, and that the states were bound, under the Articles, to accept interpretations of international law by the Federal Captures Court and Congress. That was put in unequivocal terms, applicable to all rules of the law of nations, in a highly influential 1786 Report by John Jay to the Continental Congress on U.S. compliance with the Treaty of Peace with Britain, which was unanimously approved by the state delegations to Congress:
Our national constitution having committed to us the management of the national concerns with foreign States and powers, it is our duty to take care that all the rights which they ought to enjoy within our Jurisdiction, by the laws of nations and the faith of treaties remain inviolate. And it is also our duty to provide that the essential interests and peace of the whole confederacy be not impaired or endangered by deviations from the line of public faith into which any of its members may from whatever cause be unadvisedly [sic] drawn.5
Still under the Articles of Confederation, the same characterization of the law of nations as national law, directly applicable with preemptive effects in American courts, was adopted in the New York Mayor’s Court’s unanimous 1784 ruling in Rutgers v. Waddington. There, in the most widely-publicized decision of the era by an American court, John Duane accepted arguments made by Alexander Hamilton and held that the seizure of a British Loyalist’s property during the Revolutionary War violated the law of nations. Duane declared that, notwithstanding contrary state law, customary international law limited the rights of American plaintiffs:
[T]o abrogate or alter any one of the known laws or usages of nations, by the authority of a single state, must be contrary to the very nature of the confederacy, and the evident intention of the articles, by which it is established, as well as dangerous to the union itself.6
As a consequence, even under the Articles, in a decision applauded by George Washington, the Mayor’s Court refused to apply New York legislation that imposed liability on British Loyalists in violation of applicable rules of international law. Other authority under the Articles, again approved in most political quarters, adopted the same view of the status of treaties and the law of nations, equating the two forms of international law rules as national law with preemptive effect on contrary state law.7
The Constitution: The Supremacy Clause & The Law of Nations
Article VI of the Constitution was carefully drafted to provide that all of the “Laws of the United States” have the status of the supreme Law of the Land, in both federal and state courts. In proposing Article VI for ratification, the Constitution’s drafters rejected proposals to limit the Supremacy Clause to “Acts of Congress,” instead adopting the more expansive reference to the “Laws of the United States.” That reference was deliberately not limited to congressional statutes, and encompassed common law rules (as well as congressional-executive agreements and executive orders). As a textual matter, that is clear from the definition of “Laws,” which included non-statutory forms of law, and from the other uses of the term “Laws” in the Supremacy Clause and elsewhere in the Constitution, which also clearly included non-statutory forms of law.8
More specifically, the formulation ultimately used in the Supremacy Clause was understood, and deliberately intended by the Framers, to include the law of nations. Thus, the law of nations was consistently referred to throughout this era not just as “part of our law,” but also as part of the “laws of the United States,” “laws of the nation,” “national law,” “law of the US,” law of “the U States,” “national common law,” or “law of this country.”9 Conversely, there appear to be no recorded instances during this era of the law of nations being said not to constitute part of the Laws of the United States. As a textual matter, therefore, when Article VI referred to the “Laws of the United States,” it included the law of nations as one of the sources of federal law.10
Conclusion: A Remarkable Consensus
Throughout the Constitution’s drafting and ratification, speakers from across the political spectrum of the day repeatedly made it clear that the law of nations, like treaties, would have direct, preemptive effects on state law in American courts, both federal and state, without the need for congressional implementation. Jay’s remarks in The Federalist No. 3 equated treaties and the law of nations as uniform national law and underscored the vital importance of complying with both forms of international law.
Hamilton, Madison, Wilson, Mason, and other proponents of the Constitution made statements to the same effect—declaring or assuming that the law of nations would be a matter of uniform federal law—during the drafting and ratification debates.11 For their part, Anti-Federalists did not challenge these statements and, on the contrary, cited, sometimes with concern and sometimes with approval, the fact that, under the Constitution, “[t]here is to be one Supreme Court—for chancery, admiralty, common pleas, and exchequer ..., to which are added, criminal jurisdiction, and all cases depending on the law of nations—a most extensive jurisdiction!”12 Notably, despite the vigor of opinion that attended the debates, there were no recorded contrary views on the status of the law of nations under the Constitution, either from Anti-Federalists or otherwise: the law of nations was both vitally-important to the Nation and a matter of federal law – specifically, part of the “Laws of the United States” and the “Supreme Law of the Land.”
Endnotes
1. Curtis A. Bradley & Jack L. Goldsmith, Customary International Law as Federal Common Law: A Critique of the Modern Position, 110 Harv. L. Rev. 815 (1997).
2. Mark W. Janis, America and the Law of Nations 1776-1939, at 24 (2010).
3. The Declaration of Independence, ¶¶1, 32 (U.S. 1776).
4. Gary Born, International Law in American Courts ¶¶3.B.2.a-b, 4.B.2.c & 5.B.1.a (2026).
5. 32 J. Cont’l Cong. 1774-1789, at 176, 177-78 (Roscoe R. Hill ed., 1936) (April 13, 1787) (emphasis added).
6. Rutgers v. Waddington, Opinion of the Mayor’s Court (August 27, 1784), reprinted in 1 The Law Practice of Hamilton: Documents and Commentary 392, 400, 405-06 (Julius Goebel, Jr. ed., 1964) (emphasis added).
7. Gary Born, International Law in American Courts ¶¶4.B, 5.B.1.a-e, 5.B.2,3 (2026).
8. Gary Born, International Law in American Courts ¶5.A.1-4 (2026).
9. Id. at 5.A.1-4.
10. The provisions of Article VI were paralleled by Article III’s grants of federal jurisdiction over cases arising under both U.S. treaties and, like Article VI’s Supremacy Clause, the “Laws of the United States.” As with Article VI, Article III’s references to the Laws of the United States included the law of nations—in turn confirming the scope of the Supremacy Clause. U.S. Const. art. III, §2.
11. Gary Born, International Law in American Courts ¶5.B.2-3 (2026).
12. Virginia Convention Debates (June 21, 1788), in 10 The Documentary History of the Ratification of the Constitution 1440, 1445-46 (John P. Kaminski & Gaspare J. Saladino eds., 1993) (William Grayson) (emphasis added).
