The expression “classical liberalism” rarely appears alongside words like “foreign policy.” It is often said of classical liberals that they have little to say about international relations beyond advocating free trade and economic globalization.

But what if the real issue is that most classical liberals don’t give nearly as much attention to the study of international relations (IR) as they do to economics? That at least is the thesis of Edwin van de Haar, and it is a gap that the international relations theorist and scholar of classical liberalism has sought to fill over the past twenty years.

Such is the objective of van de Haar’s latest book, Human Nature & World Affairs: An Introduction to Classical Liberalism and International Relations Theory. Not only does this book posit that a coherent IR theory can be generated out of classical liberalism, but van de Haar also thinks that it is important that people recognize that classical liberalism has much to say about international relations that goes beyond economics. Ongoing failure to grasp this, he maintains, has produced seriously truncated understandings of classical liberalism and often severe misrepresentation of the thought of important classical liberal thinkers on international relations and related subjects.

A Bottom-Up Theory

Van de Haar is adamant that an understanding of international affairs derived from classical liberal thought is distinct from realist, liberal internationalist, and, significantly, libertarian conceptions of relations between states. Central to this argument is van de Haar’s contention that a classical liberal IR theory is ultimately derived from classical liberal thought about human nature. To that extent, it is a “bottom-up” IR theory rather than one based on the top-down vistas of enlightened statesmen.

Van de Haar does not pretend that classical liberals agree upon every detail about human nature. He does, however, argue that there is sufficient consensus on this matter to mark classical liberalism off from social liberalism, libertarianism, and conservatism, and therefore their respective implications for international relations. To make his point, van de Haar outlines key differences between the assumptions of classical liberalism and the three other political philosophies through comparisons of thinkers whom van de Haar considers representative of these traditions.

Some readers will quibble about aspects of van de Haar’s categorizations. Identifying Lord Acton and Alexis de Tocqueville as conservative thinkers, for instance, struck me as odd. While holding conservative views on many topics, both men understood themselves to be what we would call “classical liberals” primarily because of the priority they accorded to liberty from unjust coercion.

Such minor criticisms aside, van de Haar’s account of the differences characterizing the four philosophical positions does identify solid foundations for a classical liberal IR theory. At its core are the ideas of particular thinkers (David Hume, Adam Smith, F. A. Hayek, and Ludwig von Mises) and their attitudes towards particular topics: namely, human nature, group identity, state coercion in international affairs, international law and international organizations, and economics.

As he works his way through these thinkers, van de Haar puts right various misconceptions about their respective ideas concerning relations between states. Take, for instance, Hume and Smith. Both deemed international free trade as part of the path to prosperity and reflective of the workings of the system of natural liberty. Neither were enthusiasts for war. In this sense, they share some positions with modern-day liberal internationalists and libertarians.

Yet, van de Haar demonstrates that Hume and Smith were far from pollyannish about international affairs. This is where their ideas are far closer to realist IR theory. Sovereign states, Hume believed, were a permanent feature of the international landscape. Tensions between them would always characterize international politics. Why? Because tensions between humans who may have reason but are also fallible, self-interested, and can’t know everything are likewise a permanent state of affairs. Occasionally, this would result in war. Imagining that it wouldn’t, Hume thought, was an error. The prospects for what would be called a Kantian perpetual peace ranged, in Hume’s view, from dim to non-existent as long as humans remained human. While diplomacy was helpful in managing relations between states, there were limits to its effectiveness.

Hume did hold that trade and international law, as expressed in the natural law jurisprudence of Hugo Grotius and Samuel Pufendorf as well as the conventions associated with the law of nations, could ameliorate relations between states. But even when the cause was judged legitimate according to the classic just war criteria, Hume stipulated that nations should think long and hard before going to war. War’s negative effects could not be underestimated.

Smith arrived at similar conclusions. Like Hume, he paid attention to the fact of unchanging constraints and their consequences for relations between countries. The capacity of human sympathy to extend beyond the level of one’s nation was, Smith insisted, limited. Indeed, while Smith cited favorably Grotius and Pufendorf’s commentaries on international law, he was more skeptical than Hume of the utility of the law of nations.

It hardly needs restating that Smith was a forceful advocate of trade liberalization. But Smith also maintained, van de Haar writes, that “as nation states became wealthier through trade, they would be more able to afford military equipment, support armies and engage in foreign wars.” This is one reason why Smith did not insist upon any necessary causation between trade and lasting peace among nations. Hume’s position was the same.

Van de Haar presents Hayek and Mises as having similarly un-utopian views of international relations. Their experience of growing up in the multinational Habsburg Empire, wartime service in the multilingual Austro-Hungarian army, and the ethnonationalist chaos into which Central Europe descended after the First World War influenced their thought about international affairs. So did the emergence of ideologically-driven regimes like Nazi Germany. These, Hayek and Mises thought, would eventually need to be resisted by Western democracies. After World War II, Hayek became increasingly bellicose towards Communist regimes and didn’t hesitate to call upon Western countries to resist Communist aggression.

Hayek and Mises’s experience of the ethnic tensions that tore apart the Habsburg Empire led them to propose various schemes for pan-European federations. Such proposals were, however, heavily tempered by their opposition to any centralization of power in international organizations. Neither were fans of the League of Nations or the United Nations. While international law was something that they took seriously, they also regarded its effectiveness as limited. In later life, Mises came to embrace Hume’s emphasis on the balance of power (a standard realist position) as one way to limit international conflict.

Above all, what characterized the reflections of Hume, Smith, Hayek, and Mises on international relations was their willingness to think beyond economic categories. Hayek and Mises’ opposition to state-to-state foreign aid, for example, flows directly from their distrust of government-run economic programs. Nonetheless, the same insights into human nature that made them market liberals and confident about economic liberty’s capacity to transform the world also inoculated Hume, Smith, Mises, and Hayek against idealistic conceptions of international relations.

This puts many of their ideas at odds, van de Haar suggests, with those who regard nation-states largely as sources of disorder. Yes, Hume, Smith, Mises, and Hayek opposed jingoism, ethnonationalism, and imperialistic political enterprises. Yet they neither disdained patriotism nor attachment to particular cultures or nations. On the contrary, they considered such things to be part of the human condition and declined to blind themselves to the implications for international order.

Van de Haar shows that a classical liberal IR theory has the potential to facilitate a relatively freer, more prosperous, and less violent world, while simultaneously immunizing us against perpetual peace delusions.

Commitments plus Prudence

Taken together, van de Haar suggests that there is sufficient commonality in the positions of these classical liberal thinkers to identify principles that define a classical liberal IR theory. Such principles, however, are wrapped up in a mantle of prudence and realism.

Here, neither prudence nor realism means Machiavellian or cynicism. Instead, prudence concerns attention to history and hard-won experience, while realism involves understanding that human nature does not change and that we must acknowledge this truth rather than ignore it.

On this basis, van de Haar identifies key concepts that characterize a classical liberal conception of international relations. They include recognition that: 1) the nation-state and national sovereignty are the basic building blocks of world affairs; 2) a degree of conflict is inevitable in international relations; 3) the balance of power injects some stability and predictability into relations between states; 4) only a limited number of rights merit international protection; 5) international organizations have roles to play but their powers should be strictly limited; 6) trade between nations is no guarantee of peace; and 7) military interventions into other countries’ internal affairs should be limited to a narrow band of cases, like genocide.

IR scholars and foreign policy specialists will notice that van de Haar’s typology clashes with priorities associated with approaches to foreign affairs that have assumed prominence in recent decades. It plainly disfavors, for instance, powerful countries attempting nation-building or using force to spread democracy abroad. But nor does van de Haar’s schema affirm liberal internationalism’s faith in international organizations’ capacity to secure something like enduring international peace if they are given the power to do so.

At the same time, van de Haar does not think that classical liberal IR theory always leads to immediately obvious foreign policy conclusions. “Going from theory to practice is never straightforward,” van de Haar states, “and the move from international relations theory to foreign policy is no exception.”

That said, van de Haar does think that particular foreign policy goals do emerge from a classical liberal IR approach. Examples include working to promote free trade or curtailing the number of international organizations and their powers. To this, I would add that van de Haar’s theory surely implies a radical decentralization of the European Union and terminating any claim on Brussels’s part to a type of supranational sovereignty.

Van de Haar is not shy about highlighting potential clashes that arise from his theory. If, for instance, classical liberalism involves accepting nation-states, then, by definition, classical liberalism acknowledges nation-state sovereignty. Such sovereignty implies national borders. This in turn means that national governments must make decisions about who and what crosses those boundaries and under which conditions.

This logic has implications for how governments treat something that classical liberals have always valued: the free movement of goods, capital, and people. Herein lies, argues van de Haar, an explanation for the spectrum of classical liberal views on topics like immigration.

Some classical liberals embrace essentially libertarian positions on this topic. In a few instances, these spill over into favoring open borders. Other classical liberals, however, support ease of movement across borders, but contend that governments are perfectly within their rights to regulate such movements to the extent that they impact national security, and the maintenance of domestic freedoms, social harmony, and respect for property rights, constitutionalism, and rule of law. These classical liberals thus hew closer to conservative views rather than some strands of libertarian opinion.

A Principled Realism

All in all, van de Haar’s conception of a classical liberal foreign policy adds up to a combination of four things. One is the application of market liberalism to the global economy. The second is recognition of nation-states and national-sovereignty as primary and fundamental, but not absolute. A third is that war should be avoided as much as possible while understanding that a war-free world is unlikely. Fourth, imperfect humans should be willing to accept imperfect solutions in international relations and thereby avoid the Scylla of utopianism and the Charybdis of raw realpolitik.

To my mind, this sounds something like the most difficult of political positions, whether domestic or international: a type of principled realism. Van de Haar’s classical liberal IR theory embodies strong normative commitments like the high value that it accords to the individual’s freedom from unjust coercion. These same principles, however, are shaped by attentiveness to permanent features of human nature that often produce conflicts within and across national borders.

It is not evident that the principled realism of van de Haar’s IR theory is likely to exert much influence at present, if only because of many contemporary classical liberals’ apparent reluctance to move beyond economics when reflecting upon international relations. Van de Haar does nonetheless show that a classical liberal IR theory has the potential to facilitate a relatively freer, more prosperous, and less violent world, while simultaneously immunizing us against perpetual peace delusions. In an eternally dangerous world, that would be no small achievement.