Introduction. Earlier this year, a law journal published an exchange between two respected law professors—a conservative and a libertarian—about whether the Constitution authorizes Congress to regulate immigration. (The Constitution does not mention immigration except to say that Congress cannot not ban certain immigration before 1808.) The conservative said “Yes,” and supported his position with some extremely liberal (!) readings of parts of the Constitution. The libertarian said, “No”—that except in special circumstances Congress could not restrict immigration (although the states could).
Surprisingly, both contributors missed the actual source of Congress’s immigration authority: the power “To define and punish . . . Offences against the Law of Nations”) (Article I, Section 8, Clause 10).
The law journal already had been published, so it was too late to join the discussion on its pages. Accordingly, I wrote an article in The Hill detailing why the “Define and Punish Clause” applies to immigration. The libertarian replied on the pages of the Volokh Conspiracy, a Washington Post blog to which he regularly contributes, and for which I have occasionally written as well.
I thought this issue was worth a full explanation of why the Define and Punish Clause covers immigration, because its applicability to immigration is not well known, even among legal experts. Accordingly, I prepared the essay below for readers interested in immigration issues. As should be apparent from this essay, I am NOT taking a stand on immigration policy, just on an issue of constitutional interpretation. This essay appeared in Josh Blackman’s Blog.
Links to some of the earlier writings appear in the essay.
Why the Define and Punish Clause Grants Congress Power to Regulate Immigration
By Robert G. Natelson
In a recent article in The Hill, I wrote that the Constitution’s grant to Congress of power “To define and punish . . . Offences against the Law of Nations” confers authority to restrict immigration. Professor Ilya Somin has responded and argues the contrary.
Before addressing his argument, I should make clear I agree with Professor Somin on several key issues about the Constitution and immigration. I agree that the original meaning of the Commerce Clause does not include a general power to restrict immigration, and that the Naturalization Clause probably does not, either. In company with him, I reject the claim that the federal government possesses extra-constitutional inherent sovereign authority—because that claim is starkly inconsistent with the ratification-era debates, the structure of the Constitution, and the text of the Tenth Amendment.
Where we differ is about whether the power to “define and punish Offences against the Law of Nations” includes authority to restrict immigration.
“The Law of Nations” was the usual 18th century term for international law. Most of the law of nations governed how nations interacted with other nations. However, some aspects governed how they interacted with foreigners and a few aspects—such as the law merchant—regulated how citizens of different countries interacted with each other.
The law of nations was based on natural law, custom, and international agreements. However, the rules were not always clearly defined, and they were not self-executing. For this reason, legislatures adopted implementing statutes. Examples of such statutes were those protecting safe-conduct passes from disrespect and foreign ambassadors from insult. The Define and Punish Clause granted Congress authority to adopt implementing measures.
The law of nations held, as a general principle, that nations should not harm each other. Hence, it provided that nations must refrain from unauthorized incursions into other nations’ territory. To violate international law, the unauthorized entry need not be led by a foreign government. As the Founders’ favorite international law scholar, Emer de Vattel observed, “Private persons, who are members of one nation . . . may injure a foreign sovereign.” Immigration statutes implemented the “no unauthorized entry” norm against “private persons” from other countries.
Professor Somin acknowledges that “the law of nations did indeed assume that each state has the authority to restrict the entry of aliens, largely as it sees fit.” But he notes that the mere fact that the law of nations authorized a sovereign to adopt legislation did not render the legislation part of the law of nations. For example, the law of nations recognized a sovereign’s prerogative to enact statutes forbidding murder. However, most murders were not offenses against the law of nations. Moreover, if it were true that any statute consistent with international jurisprudence were part of international jurisprudence, the Define and Punish Clause would empower Congress to adopt any ordinary police legislation permitted by international law. Such a sweeping grant of power to Congress would be inconsistent with the Founders’ design.
On these points Professor Somin is correct.
On the other hand, some domestic statutes surely did define offences against the law of nations. An example is a statute prohibiting a citizen from insulting or impeding a foreign ambassador. Thus, to state that the Define and Punish Clause does not authorize all domestic laws does not answer the question of which domestic laws it does authorize. Is a statute restricting immigration in the class with ordinary murder laws or in the class with protections for ambassadors? Immigration limits have international implications that ordinary murder laws do not have. So reasoning would seem to place immigration restrictions in the “law of nations” category.
But questions of constitutional meaning cannot be answered through pure reason, however acute. Nor does the constitutional answer lie in what we moderns think international law is or should be—a mistake into which Professor Somin’s essay slips once or twice.
At least to an originalist who follows Founding-Era norms of interpretation, the meaning of a constitutional term is fixed by the understanding of those who ratified it or, in absence of sufficient coherent evidence on that subject, by the original public meaning. When, as here, the constitutional debates provide little relevant evidence on the sense of a legal term, our best evidence of its meaning may be Founding-Era jurisprudence. (I say “may be” because contemporaneous congressional and state records are sometimes more helpful.)
To a modern reader, some of the classifications adopted by 18th century jurisprudence appear arbitrary. Yet those classifications often serve to define constitutional meaning. The framers treated bankruptcy and commerce separately, despite their interrelated nature, because they were distinct legal categories. Similarly, the legal phrase of “to regulate Commerce” encompassed travel by ship but not (most) travel by foot. So under the Constitution’s original legal force, the power to regulate commerce included boat travel from Canada but not (usually) walking across the border.
Helpful to grasping international law jurisprudence as the Founders understood it are three treatises they held in high esteem: Samuel Pufendorf’s 17th century work, Of the Law of Nature and Nations, and two 18th century works: Emer de Vattel’s The Law of Nations and Blackstone’s Commentaries.
Vattel wrote that the law of nations derived from the natural law applicable to individuals, as modified by convention and by the special circumstances of sovereigns: “[C]onsequently, the law of nations is originally no other than the law of nature applied to nations” (emphasis in original). Indeed, both Vattel and Pufendorf frequently drew upon rules of natural law applicable to individuals to deduce or justify substantive rules of international law. By way of illustration, here is how Pufendorf justifies immigration restrictions:
The Case is somewhat like that of a private Man, who in his House or Gardens, possesses some rare Curiosity, or other valuable Sight; such an one does not apprehend himself tied freely to let in all Spectators . . . And this seems the more reasonable, because the Grounds of prudent Caution and Suspicion are so numerous. . . .
And farther, that it seems very gross and absurd, to allow others an indefinite or unlimited Right of traveling and living among us, without reflecting either on their Number, or on the Design of their coming; whether supposing them to pass harmlessly, they intend only to take a short view of our Country, or whether they claim a Right of fixing themselves with us for ever. And that he who will stretch the Duty of Hospitality to this extravagant Extent, ought to be rejected as a most unreasonable, and most improper Judge of the Case.
As to our main Question, it is look’d on by most as the safest way of resolving it, to say, That it is left in the power of all States, to take such Measures about the Admission of Strangers, as they think convenient . . . .
I suppose Professor Somin might respond that Pufendorf was merely asserting the power of nations to exclude foreigners—that Pufendorf was not saying the intrusion violated the law of nations. But this does not seem justified by the context. Pufendorf was engaged in the common methodology of using rules of domestic law to deduce rules of international law. Domestic law not only gives permission to a householder to decide to exclude. Domestic law also makes it an offense to disregard the householder’s decision. I see no reason why international law would not encompass both the decision to exclude and unauthorized disregard of that decision. As noted earlier, immigration laws are not purely domestic in their effect; they have important international implications.
Blackstone understood this passage the same way I do, and for purposes of constitutional interpretation Blackstone’s exposition matters a great deal. Explicitly relying on this passage, Blackstone wrote, “Upon exactly the same reason stands the prerogative of granting safe-conducts, without which by the law of nations no member of one society has a right to intrude into another. (emphasis added).” To Blackstone, then, the law of nations does not merely grant a sovereign the right to exclude. A violation is itself an offence against the law of nations.
Now we turn to Vattel’s treatise. It consists of four books. The first was entitled “Of Nations considered in themselves.” A major theme of this first book is the derivation of rules of governance from natural law principles. Despite the title, the book goes beyond questions of internal governance to deduce conclusions about the law of nations. Among those conclusions:
* “A nation or state has a right to every thing that can help to ward off imminent danger;”
* nations may limit or ban imports;
* they may refuse to trade with others; and
* they may restrict emigration and immigration, taking into consideration a range of factors, including available land, health concerns, avoiding religious strife, and factors of safety and culture. Indeed, the nation “has a right, and is even obliged, to follow, in this respect, the suggestions of prudence.”
Now, these seem like rules of international law to me. And in respect to immigration at least, they go beyond mere permission: They extend to obligation—for a sovereign “is even obliged” to legislate according to likely consequences.
Vattel further supports the conclusion that the law of nations includes the substance of immigration statutes. In this book, he mentions a rule among some European states denying citizenship to foreigners. Vattel characterizes the rule—not merely the authorization—as “the law of nations, established there by custom.” Professor Somin observes that this custom regulated citizenship rather than immigration. But that distinction actually cuts against his argument: If even an internal citizenship rule dealing with foreigners—a rule central to the life of a polity—is part of the law of nations, then a limit on foreigners crossing the border is one a fortiorari. (As Professor Somin correctly states, Vattel didn’t like the custom of denying citizenship to foreigners. But that is wholly beside the point.)
Yet, perhaps one might object that Vattel’s first book is really only about “Nations considered in themselves,” and that we should therefore be cautious about treating its conclusions as part of the law of nations.
So let us examine Vattel’s second book. Its title tells us it is wholly about the law of nations: “Of a Nation Considered in its Relation to Others.” (The third and fourth books are about war and peace, respectively.) Here are some passages from the second book, presented in order of appearance:
As every thing included in the country belongs to the nation—and as none but the nation, or the person on whom she has devolved her right, is authorised to dispose of those things,— if she has left uncultivated and desert places in the country, no person whatever has a right to take possession of them without her consent. Though she does not make actual use of them, those places still belong to her: she has an interest in preserving them for future use, and is not accountable to any person for the manner in which she makes use of her property.
* * * *
Since the least encroachment on the territory of another is an act of injustice . . . the limits of territories ought to be marked out with clearness and precision.
* * * *
We should not only refrain from usurping the territory of others; we should also respect it, and abstain from every act contrary to the rights of the sovereign: for a foreign nation can claim no right in it.
* * * *
The sovereign may forbid the entrance of his territory either to foreigners in general, or in particular cases, or to certain persons, or for certain particular purposes, according as he may think it advantageous to the state. There is nothing in all this, that does not flow from the rights of domain and sovereignty: every one is obliged to pay respect to the prohibition; and whoever dares to violate it, incurs the penalty decreed to render it effectual. But the prohibition ought to be known, as well as the penalty annexed to disobedience: those who are ignorant of it, ought to be informed of it when they approach to enter the country.
* * * *
Since the lord of the territory may, whenever he thinks proper, forbid its being entered, he has no doubt a power to annex what conditions he pleases to the permission to enter. This, as we have already said, is a consequence of the right of domain.
Perhaps one might rejoin, “Here again, Vattel says only that the law of nations permits sovereigns to restrict immigration; he does not say that violations are part of the law of nations.” On the contrary, though, Vattel does more than describe the prerogative of the sovereign to exclude. In this book (remember: focusing on international norms) Vattel also prescribes the duty to obey:
* “We should not only refrain from usurping the territory of others; we should also respect it, and abstain from every act contrary to the rights of the sovereign;” and
* “[E]very one is obliged to pay respect to the prohibition; and whoever dares to violate it, incurs the penalty decreed to render it effectual.”
Even if these passages of obligation were absent, I don’t think it is the most natural reading of the text to infer that the right to enact a restrictive statute is a component of international law but violation of the statute is not. I doubt many Americans reading Vattel during the Founding Era would think a book entitled “Of a Nation Considered in its Relation to Others” was telling them, “The law of nations authorizes restrictive immigration statutes but is wholly agnostic about their violation.” Certainly Vattel never says that.
One last point—not fully germane, but worth mentioning. Professor Somin writes, “But in the eighteenth century, and even today, states have no international law obligation to prevent the peaceful migration of their citizens to foreign nations that might wish to exclude them.” Vattel, at least, may well have disagreed:
If a sovereign, who might keep his subjects within the rules of justice and peace, suffers them to injure a foreign nation either in its body or its members, he does no less injury to that nation, than if he injured it himself.
* * * *
Finally, there is another case where the nation in general is guilty of the crimes of its members. That is when by its manners and by the maxims of its government it accustoms and authorizes its citizens . . . to make inroads into neighboring countries.
* * * *
Author’s note: Since this essay was written, I have encountered more sources influential in the Founding Era that assert that migration across national borders—both immigration and emigration—was a subject within the “Law of Nations” as our Founders used the term. Late in the 18th century Georg Friedrich von Martens authored a book called the Summary of the Law of Nations. Martens wrote that “From the moment a nation have taken possession of a territory . . . they become the absolute and sole proprietors of it, and all that it contains; and have a right to exclude all other nations from it . . . It belongs to the possessors, of course, to make the distribution of their territory, and every thing attached to it.” In his chapter entitled “Of the rights of the sovereign as to the property of the territory: of imposts,” he wrote: “A foreigner enjoying the protection of the state, cannot, while he remains in it, expect to be entirely exempted from imposts. Besides, it may be made a condition of his admission. He may even be loaded heavier than the born subjects of the state, if no treaty between this state and his own specifies the contrary.” [Italics added.] (Obviously, if the power to impose conditions on admission is part of the law of nations, so is the power to exclude.)
In the 18th century emigration was a more significant issue than immigration, so Martens added chapters on the right of nations to bar emigration and the related right to tax it.
The seminal work on the law of nations in the modern era was Hugo Grotius’s The Rights of War and Peace. It was written in the 17th century, but still widely used in the 18th. For the Founders, the definitive versions were those translated and annotated in the 18th century by Jean Barbeyrac.
Grotius also treated trans-border migration as a subset of international law. Book II, chapter 2 of his work contained a discussion of when states should accept foreign visitors and when they need not. Grotius argued that states should receive people expelled from their own lands and people wishing to settle on unoccupied territory, but not immigrants seeking to settle in occupied territory. In his annotations, Barbeyac disagreed with Grotius to this extent: Barbeyac contended that a nation had no obligation to accept immigrants who wished to settle on unoccupied territory.
Arguably the position of Barbeyac, an 18th century writer, is stronger evidence for 18th century international law than Grotius’s older statement. However, for constitutional purposes, the merits of the dispute are irrelevant. What is relevant is that Grotius, Barbeyac—and apparently all the other authorities the Founders relied on—considered goverance of immigration to be part of “the Law of Nations.”