The Yale Law Journal


The Fog of Certainty

29 Sep 2009

A Response To

In The Constitutional Power To Interpret International Law, Michael Paulsen argues that “[t]he force of international law, as a body of law, upon the United States is . . . largely an illusion.” Rather than law, international law is “policy and politics.” For all the certainty with which his argument is advanced, however, it cannot survive close scrutiny. At its foundation, Paulsen’s essay rests on a pair of fundamental misconceptions of the nature of law. Law is not reduced to mere policy, to begin, simply because it can be undone. The sources of law, meanwhile, are not singular, but plural. Even were international law not domestic law, it would still be law.

Paulsen insists, to the contrary, that international law is not law, because Congress, the President, and the courts can displace it. Yet what distinguishes binding law from discretionary policy cannot possibly be that it may not be undone. Were that true, little if anything would be law. The distinguishing characteristic, instead, is that the displacement of law requires some substantive standard to be met and some prescribed process followed.

Professor Paulsen’s misconception about the sources of law, in turn, arises from his unwillingness to analyze international law as anything more than a subset of U.S. law. International law may have force—and even be “binding”—entirely apart from its status as domestic law. This would not be true were the Constitution to be understood not simply as failing to give force to international law in certain cases, but as affirmatively negating the possibility that international law could exert such force. Yet this would imply a further misunderstanding—one of the Constitution itself.

These errors, it bears noting, are fairly basic. Before considering them in greater detail, therefore, it is worth considering how Professor Paulsen manages to go so completely astray. Here, the invocation of Clausewitz’s “fog” of war—with its attendant distortions and misperceptions—is perhaps telling. A species of just this may be at work here, with Professor Paulsen misled not by the fog of war, but by an exaggerated sense of certainty in the idiosyncratic premises with which he begins, and the heterodox conclusions he hopes to establish. Such certitude is perhaps most visible in the sharply dismissive tone of the essay. Less apparent—but more consequential—is Professor Paulsen’s selective use of authority. I begin with a few words on the latter, thus, before exploring the twin errors that arise from Paulsen’s exaggerated sense of certainty, and which ultimately undermine his claim that “[i]nternational law is not, in the main, law for the United States.”

I. The Use, Non-Use, and Abuse of Authority

Professor Paulsen’s issues with authority begin with his lack of citation for even some of his most striking claims—among them that “none of the branches is literally bound by the views or actions of the others” and that Congress’s power to define “Offences against the Law of Nations” is “best understood as bounded by the President’s power to command the nation’s military forces . . . .” Moreover, where the essay does offer authority for its arguments, the most common source is Professor Paulsen’s own—famously idiosyncratic—prior work. Where the analysis of others is cited, finally, it is subject to a strict litmus test: agreement with the view Professor Paulsen seeks to advance. Reading the piece, thus, one might be forgiven for thinking that scholars are in agreement that customary international law is not federal law and that the President can disregard “unconstitutional” decisions of the Supreme Court.

All of this, of course, is misleading to the reader. It is the implications for Professor Paulsen’s own analysis, however, that concern me here. Ultimately, he gets things dramatically wrong, offering conclusions that simply cannot stand the light of day. Why? At least in part, I believe, it is because his arguments go untested against the views of those who might disagree.

Even more damning than its omissions of relevant authority, however, are the essay’s errors of commission, particularly in its treatment of Supreme Court precedent. Where the Court agrees with Professor Paulsen, its decisions are meticulously reviewed, in the spirit of not merely dispositive, but compelling, authority. No mention is made of close votes, limited holdings, or controversy. Sanchez-Llamas v. Oregonwas thus “forthright” and “unabashed” in its holding. Medellín v. Texaswas “rightly” decided. By contrast, decisions that cut against Paulsen’s claims—most of them, it turns out—are given the back of the hand. They are “highly controversial,” “deeply and bitterly divided,” wrongly decided, issued only because the Supreme Court had no other choice, or—in the most memorable case—best ignored, “so as to save the Court from the embarrassment of contradicting the Constitution . . . .”

I do not mean to suggest that legal scholars should limit themselves to a doctrinal approach to the Court, in which the Constitution, international law, and law generally are simply what the Court says they are. But as scholars trying to find, rather than promote, answers, we do well to be careful in our picking and choosing. A close vote is a close vote, whether it is for me or against me. Likewise, a binding decision is final regardless of whether it supports or contradicts my proposition. If Sanchez-Llamas v. Oregon and Medellín v. Texastell us something important about the subject at hand, then so do The Paquete Habana, Charming Betsy, Dames & Moore, Garamendi, Hamdan, Boumediene, and other decisions, all of which Professor Paulsen is too quick—and determined—to dismiss. One cannot claim to offer a positive account of constitutional practice, ultimately, if one insists on ignoring actual constitutional practice.

II. The Nature of Constraint: Legal and Political

Rather than a minor quibble with Professor Paulsen’s style, his misuse of authority deserves emphasis, given the pair of misunderstandings of the nature of law that arise from it. The first of these—as described at the outset—is his notion that law is not law, but policy, where it can be undone. Seemingly binding international law norms are not law, Professor Paulsen seems to believe, because they can be displaced by subsequent decisions of Congress, the President, and the courts. But can this possibly be true?

Surely not, since the very same can be said of most domestic law as well. Congress can displace prior legislation, as well as executive orders, agency regulations, and even some decisions of the Supreme Court. The President—especially one empowered along the lines Professor Paulsen would favor—can displace prior executive orders, some agency regulations, and perhaps much more. The Supreme Court can invalidate any of the above. And if we embrace Professor Paulsen’s strong-form departmentalism, Congress and the President can thereafter choose to ignore the offending decision of the Court. By Professor Paulsen’s measure, then, the U.S. domestic legal system turns out to be quite lawless.

But we are not lawless. Professor Paulsen, instead, misunderstands what law is. Or, in his own terms, what makes something a “political” versus “legal” constraint. He is at least partially right, of course, to suggest that the international law obligations of the United States can be displaced by subsequent domestic legislation. But a constraint does not cease to be so simply because it can be undone. In the first order, this is true as a conceptual matter. That “I can repeal the law” does not mean that “it fails to bind me even when I have not yet repealed it. Hobbes is wrong that, if you can free yourself at will, then you are already free . . .” It is no less true as a practical matter. The constraints of international law cannot be undone at will. Rather, to undo an obligation under international law—like one under domestic law—some threshold standard must be met and some prescribed process followed. By contrast with mere policy, it cannot be undone by fiat. As law, it can only be undone by law.

No claim of exclusivity or equivalence need follow. Certain “laws” may enjoy a political force equal to their legal force. The nature of their constraint, as such, may be both political and legal. The political implications of the repeal of domestic law, meanwhile, may well be greater—even far greater—than any rejection of international law. Yet this is not less true across divergent domestic settings: amendments to the U.S. Constitution are subject to far more stringent political oversight than are zoning variances in the City of New Haven. Both zoning rules and the Constitution remain legal constraints, however, no less than international law.

III. There Can Be Only One

That international law—like most law—can be displaced by subsequent domestic initiative, then, does not make it policy rather than law. Professor Paulsen’s assertion to the contrary, however, turns out to be even more problematic than the foregoing suggests. For even if we assume, arguendo, that international law is not law in any domestic sense, it would still be law.

Here we find the essay’s second misconception of the nature of law. This begins with Professor Paulsen’s embrace of an Austinian notion of law as limited to the coercive commands of a singular sovereign. Further, in Professor Paulsen’s account, a rule cannot be law for the United States, unless it is law of the United States. As above, however, these conclusions do not survive close scrutiny.

International law constitutes its own system of rules and processes, to which the United States may be obliged and held liable. Consider the case of the World Trade Organization (WTO), which Professor Paulsen assiduously avoids. The WTO is founded on a highly detailed set of rules, to which the United States has committed itself. Further, it offers a mechanism by which adherence to those rules can be tested, including trial-level proceedings and subsequent appellate review. At the end of this process, potentially costly sanctions can be—and have been—imposed on parties found to be out of compliance, including the United States.

Professor Paulsen would have us regard these sanctions as “illusory,” as mere “policy and politics.” But why? At least in part, one might surmise, because of the lack of a WTO infantry charged to implement its sanctions. Such narrowly positivist accounts of the nature of law have largely been abandoned, however, even in domestic settings. Law, we now understand, consists of far more than what the army will enforce.

Overlooking all this, Professor Paulsen insists that “[t]he question of international law compliance is one of international politics and international relations, not one of binding U.S. law.” But this misses the obvious middle ground. Even if international law were not binding U.S. law, neither would it be “international politics and international relations” alone. Rather, it would be international law. See, e.g., Robert B. Ahdieh, Between Dialogue and Decree: International Review of National Courts, 79 N.Y.U. L. Rev. 2029, 2095-96 (2004); Paul Schiff Berman, Global Legal Pluralism, 80 S. Cal. L. Rev. 1155, 1230-31 (2007).

Professor Paulsen’s error, however, goes beyond a sub rosa attempt to resuscitate the long-moribund claim that international law is not law, for lack of coercive force behind it. He might be right to cast international law as mere policy for the United States, if the Constitution could be read to assert a claim of exclusivity in its statement of “what the law is.” Professor Paulsen, in fact, might be understood to endorse just this view:

While international law may prescribe that some exercises of the decision of the United States to engage in war are unlawful within the regime of international law, such restrictions may not interfere with Congress’s (and the President’s) constitutional powers. They are, in U.S. domestic constitutional law terms, unconstitutional purported restrictions on U.S. actors.

This reading, however, erroneously equates a lack of constitutional provision for some constraint with that constraint being unconstitutional. That the Constitution allows Congress or the President to do something thus need not be understood as preventing some other regime from precluding that very conduct. And similarly, that the Constitution states that the President enjoys certain powers and is precluded from doing certain things is not the same thing as a statement that he or she must do those things or may do anything else he or she chooses. If it were, then nothing else—international law included—could limit the President’s powers. Or more precisely, no government official could—consistent with his or her constitutional obligations—embrace such a limitation. The Constitution, however, does not state anything of the sort.

Congress constrains presidential power all the time, in ways that go well beyond the text of Article II. Justice Jackson’s tripartite scheme in his Youngstown Sheet & Tube Co. v. Sawyer concurrence might even be read to endorse as much, with its recognition that presidential authority expands and contracts in ways beyond the bare outline of executive power offered in Article II, as Congress variously acts and fails to act. Broadly, one might plausibly see the contrast between the “formidable list of enumerated powers under Article I” and the “very general language” of executive power in Article II to suggest a reading of the latter as something less than a complete and exclusive statement of the parameters of presidential power.

I do not, to be clear, mean to suggest that the Constitution can never be understood to offer an exclusive statement of applicable law. The maxim of expressio unius est exclusio alterius, which teaches that the express mention of one or more things in a class excludes other things of that class, may support this result in some settings, as perhaps with the statement of necessary qualifications for service in Congress. Professor Paulsen fails to demonstrate, however, why this should be true as to the Constitution’s provision for Congress’s declaration of war and the President’s pursuit of it. Given the lack of any enumerated constitutional “qualifications” of those powers, in fact, one might plausibly favor just the opposite conclusion.

This is important, because it means that there is nothing to prevent the President and the Senate from agreeing to at least some international constraints on congressional or presidential power. Surely there is some limit to how far they might go down that path. Presumably, they could not agree to allow “faceless bureaucrats” in Geneva to dissolve the presidency at will. But such slippery-slope claims generate more heat than light. The question raised by Professor Paulsen’s essay is whether the President and the Senate may agree—as they did with the Geneva Conventions, the Convention Against Torture, and elsewhere—to limit the conduct of the President in his or her pursuit of congressionally authorized war. That the Constitution itself does not itself impose such limits, I would argue, does nothing to suggest that the political branches are constitutionally disabled from advancing the national interest in that way.


Professor Paulsen’s claim is not, to be clear, that international law functions differently—or enjoys some lesser stature—than domestic law. Nor does he simply suggest that international law stands on less stable political ground and is hence more susceptible to repeal. Each of these propositions might warrant support—even among the “clique” of international law scholars. The insight that Professor Paulsen hopes to advance, however, is rather more extreme. International law does not mean less than domestic law; at least as law, it means nothing. No authority beyond his own certainty in this proposition, however—be it the Constitution, Supreme Court precedent, congressional legislation, or executive decree—can get him there. As Professor Paulsen points out, there is a fog—but it is not in international law.

Robert Ahdieh is the Professor of Law & Director, Center on Federalism & Intersystemic Governance, Emory University School of Law. A.B., 1994, Princeton University; J.D., 1997, Yale Law School.

I am grateful to David Bederman, Jeff Dunoff, David Fontana, Philip Hamburger, Robert Schapiro, Peter Spiro, Carlos Vazquez, and the editors of The Yale Law Journal Online, for their helpful counsel and assistance with this piece. Needless to say, however, the conclusions offered are mine alone.

Preferred Citation: Robert Ahdieh, The Fog of Certainty, 119 Yale L.J. Online 41 (2009),