Statements such as “public policy X is (or is not) in the national interest” are omnipresent. For example, Peter Navarro and Greg Autry claim that “some American CEOs” are acting against “our national interest.” In reality, the concept of national interest is, at best, meaningless. At worst, the concept of national interest is a tool of tyranny because it justifies imposing the preferences of some individuals on others. Under the excuse of the national interest, protectionist wars and even real wars have been waged, and minorities allegedly not national enough have been oppressed. The national interest is used against both foreigners and fellow citizens.

The Public Interest The national interest is simply the public interest where the public is the nation. So consider the more general concept of public interest. Economists have shown that in a society composed of individuals with different preferences, the public interest does not exist. In technical terms, if the preferences of all individuals are to count equally, a coherent “social welfare function” does not exist. As I previously showed, the political “we,” which is the subject of the public interest, is meaningless. A complete proof is technical; indeed, Kenneth Arrow received the Nobel prize partly for his proof. But illustrations can be grasped intuitively. Consider three alternative public policies, P, Q, and R, which each voter ranks on his preference scale. If all individuals have identical preferences, there is clearly a “public interest,” which is the same as the interest of any single voter. In the real world, of course, individual preferences differ. It will not work to arbitrarily define the public interest as the interest of the majority. It is easy to show examples in which voting outcomes are inconsistent: the electorate may choose P over Q, Q over R, but R over P. Is it P or R that is in the public interest? There is no way to know, and so there is no clearly defined public interest. Given different individual preferences, a meaningful “public interest” would have to be a common interest, something that all members of the public consider to be in their own personal interest. A so-called “public good” (or service) is the paradigmatic case. But there are not many such things once costs are apportioned. Only general and abstract goals or ideals can meet the test, such as maintaining peace or not blocking general prosperity. And it is conceivable that even these don’t meet the test. Some people are probably hostile to peace and/or general prosperity. A common interest is arguably what Adam Smith meant the few times he invoked the “public interest” or related concepts such as the “interest of society” or “the public good.” He never once mentioned the so-called national interest, which brings us to our specific topic.

The Problems of the National Interest The public interest can be given a more concrete content by limiting the diversity of individual preferences. If all people who don’t like cheese are excluded, a common interest in subsidizing cheese making can, perhaps, be identified. But there is another, less demanding way to find some common interest. If all voters in a certain group rank different things on a similar but not identical scale—technically, if they have unimodal preferences—they will at least avoid inconsistent electoral outcomes and cycling majorities (between P and R, as we saw above). Since a nation is more homogeneous or less “multicultural” than a random group of individuals, its members’ preferences are more likely to be similar. Thus, the national interest may appear more meaningful than the public interest. In his recent book in defense of nationalism, Yoram Hazony defines a nation as a sort of large tribe “with a common language or religion, and a past history of acting as a body for the common defense and other large-scale enterprises.” These features mean that preferences are somewhat similar. In this view, the national interest is not an empty concept. We would still want to know why language and religion are so important. By his definition, Switzerland, which has four official languages, is not a nation. Hazony would claim that within each nation, the national interest is better defined and more desirable than any non-national public interest. But this claim is a dangerous illusion, for at least three reasons. First, even in a relatively homogeneous nation, individuals will still not have identical preferences. Common interests encompass a larger domain—that is, they relate to more goods and activities—but they still attach to relatively abstract pursuits rather than to concrete choices. Even if everybody likes cheese, individuals don’t like the same kinds of cheese. Cheese, therefore, cannot be a common interest, except if what is meant is the freedom to choose the cheeses one likes. Between the public and the national interests, then, there is only a difference of degree: more preferences may be similar among individuals in the same nation than within a non-national public, but they will still not be identical. Note that even if all people in a nation had similar preferences, they would not all face the same circumstances. We all might like Stilton, but Stilton is expensive. So some lower-income people would not buy it. Their interests, defined in terms of choices instead of preferences, would still diverge. Either the national interest matches the interests of all of the nation’s members, or it matches the interests of only some members. In the latter case, it is an abuse of language to call it the national interest. In the former case, the national interest is just a common interest shared by all nationals. To see how a common interest is not obvious in so-called nations, ask yourself: what are the common preferences of, say, a typical rural West Virginian and a New York urbanite?

How National Interest Leads to Tyranny Take, again, the example of protectionism. Not all individuals will prefer national cheeses, which implies that protectionist measures against foreign cheeses cannot be in the national interest. Protectionism cannot be in the national interest because any protectionist measure will hurt at least some individuals. For example, tariffs on foreign cheeses raise cheese prices (foreign and domestic) and hurt domestic consumers. Protectionist measures can be in the interest of a minority of nationals—or, in rare cases, in the interest of a majority—but they cannot be in the interest of all because they reduce the total volume of goods and services available for consumption in the country, as the law of comparative advantage shows. The second problem with the national interest is that the policies it justifies are likely to be more oppressive of minorities than policies based on a more general public interest in a non-national or “multicultural” country. One defense of the nation and its interest was suggested by Carl Schmitt, the late German legal theorist. Schmitt seemed to recognize the right of a democratic majority to expel a minority viewed as inimical, so that the nation could become a real, homogeneous nation. To the extent that Schmitt’s theory of the state is normative and not just positive, we should not be surprised that he “sided with the Nazis after 1933… and came to be perceived as the ‘Crown Jurist’ of National Socialism.” Oppression of minorities by national majorities is a common historical occurrence. Most of today’s nationalist or secessionist movements seem to be illiberal (against classical liberalism) or at least seem to appeal to important illiberal clienteles. Schmitt’s theory reminds us that we can easily define a public or national interest if we exclude the preferences that don’t fit. The national interest is then simply what the rulers representing the national majority claim it is. They can even argue “national interest” to impose their own non-majority preferences. Any conception of nationalism based on some sort of collective or organic entity is oppression waiting to happen. A third problem with the national interest is that the homogenization of individual preferences carries costs for the nationals themselves or for a large number of them, even if state propaganda tries to hide these costs. Diversified preferences, at least within a certain range, carry information and promote experimentation and innovation, from which wealth and individual flourishing spring. Hazony suggests that the diversity among national states compensates for this flaw. Although this is partly true, the benefits of international diversity are hard to capture for people who don’t travel much, don’t speak foreign languages, or don’t spend time living in different countries. In the United States, such people are a large majority. Moreover, the national interest is typically used to justify protectionism, which means restricting the access of citizens to foreign goods and services and the diversity and competition they represent.

A Liberal “National Interest”? If we accept that individual liberty is the major political value, both the public interest and the national interest are dangerous ideas because they tend to substitute government choice for individual choice. But can’t we imagine a nation whose common interest would be recognized as individual liberty—instead of, say, national cheese? Can there be a liberal nation? One way to give a positive answer is to rephrase liberty in terms of consent. We can imagine, as James Buchanan did, an implicit social contract that requires unanimous consent, implying that everybody has to consent to limitations on his own liberty—for example, taxes for national defense and interior peace. Arguably, this is how America was founded (although Loyalists had to decamp) or at least came to be seen by most of its inhabitants. Perhaps evolved law and traditions can lead to the same sort of liberty, as, arguably, it did for a while in the United Kingdom and some Commonwealth countries. Could we speak of a public or national interest in that context? For James Buchanan (and Gordon Tullock), the public interest was conceivable only in terms of the decision-making rules established by a conceptually unanimous social contract or constitution. Individuals could accept having some of their preferences traded off if that was part of the constitutional bargain they made. But Buchanan was scornful of the expression “public interest,” which he nearly always put in quotation marks. He wrote: Political scientists, and others, often refer to “the public interest” as something that exists independently of the separate personal or private interests of the individual members of a community. The approach taken here does not recognize the existence of such a “public interest.”

There is no public interest because no public can have a self-interest the way an individual does. This is also true for the “national interest,” a term Buchanan used only once, pejoratively, in his published work.” Consider protectionism again. The parties to a unanimous social contract would likely not grant the state the power to control what they import or export, any more than they would accept restrictions on what they buy or sell within the country. Buchanan saw open immigration as a different issue. “Buchanan explains that the social philosophy associated with liberal political economy supports the open movement of goods and services,” writes Richard Wagner, “but does not support the free migration of people.” Even if a country is conceived of as a club with restricted membership, foreigners’ welfare must be otherwise factored in. Note that the Bill of Rights does not include the words “national” or “American.” John Hicks, the Nobel economist, described vividly how British classical liberalism was non-national: The Manchester Liberals believed in Free Trade not only on the ground of Fairness among Englishmen, but also on the ground of Fairness between Englishmen and foreigners. The State, so they held, ought not to discriminate among its own citizens; also it ought not to discriminate between its own citizens and others.

Summing up Perhaps we can tolerate the use of “public interest” not to mean, literally, the impossible aggregation of the preferences of all individuals but, in Adam Smith’s fuzzy way, to refer to a common interest in individual liberty. Perhaps. But the concept of national interest cannot be dissociated from the idea that some individuals impose concrete preferences on others—even within a country, as in the case of protectionism. The “national interest” smacks of an unconditional loyalty to one’s nation-state. It seems ordained to some collective or organic interest over and above the individuals’ interests. In brief, the national interest can have only an authoritarian meaning.