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date: 01 December 2021

Liberalism and Securityfree

Liberalism and Securityfree

  • John M. Owen IVJohn M. Owen IVWoodrow Wilson Department of Politics, University of Virginia


Liberalism has always been concerned with security, albeit the security of the individual; institutions, including the state, are all established and sustained by individuals and instrumental to their desires. Indeed, liberalism cannot be understood apart from its normative commitment to individualism. The tradition insists that all persons deserve, and it evaluates institutions according to how far they help individuals achieve these goals. Nor is liberalism anti-statist. Liberal theory has paid particular attention to the state as the institution defined by its ability to make individuals secure and aid their commodious living. Although liberal security literature that only examines individual states’ foreign policies may be guilty of denouncing the role of international interaction, the general liberal claim argues that the international system, under broad conditions, permits states choices. As such, for liberalism, states can choose over time to create and sustain international conditions under which they will be more or less secure. Liberalism’s history can be traced from the proto-liberalism in the Reformation to the emergence of the social contract theory and neo-theories, as well as liberalism’s focus on increasing security. Meanwhile, current debates in liberalism include the democratic peace and its progeny, reformulations of liberal international relations (IR) theory, and meta-theory. Ultimately, liberalism’s most striking recent successes concern the democratic peace and related research on democratic advantages in international cooperation. Liberalism is a useful guide to international security insofar as individuals and the groups they organize affect or erode states.


  • Security Studies


Liberalism is a tradition in political theory that takes individual persons as its units of analysis. Liberalism has always been concerned with security, albeit the security of the individual; institutions, including the state, are all established and sustained by individuals and instrumental to their desires. In recent years, liberal scholarship in international security has adopted realist language by treating states as actors, and its distinctive contribution has been its insistence that foreign policies and international outcomes vary with the types of state, particularly their domestic institutions. In contrast to the claims of realists, liberals argue that liberal democracies compete better and are more secure in an anarchical international system. Seen in its fullness, liberalism also expects transnational networks to build and sustain international institutions to constrain states and make people more secure. Liberalism overlaps partially with both rationalism and constructivism and should not be seen as competing with either. Although liberalism does not necessarily predict an imminent demise of the state and the states system, its implicit functionalism opens it to that possibility: if states no longer make people secure, they may be replaced at some point. Thus liberalism’s strength – its conceptual taming of the state – also reveals one of its weaknesses: it slights raison d’état by ignoring the incentives for even liberals to think like the state once they capture it.



Liberalism is a robust tradition in political theory that depicts individual persons, rather than groups or institutions, as the primary actors (Keohane 1989; Zacher and Matthew 1995). Individuals form groups and construct and sustain institutions – classes, ethnic groups, states – but the individuals retain the ability to influence or even capture these groups and institutions. While often recognizing emergent phenomena at higher levels of analysis, liberalism always keeps at least one eye on the individual level. Analysis is possible at that level because, for liberalism, individuals have some decisive feature in common across time and space, be it rationality, rights, the capacity to choose, a moral sense, or consciousness. Beyond these formal properties, liberalism makes various substantive claims about individuals. Historically, these have included the fundamental goals of self-preservation and “commodious living” (Hobbes 1968) – of security and prosperity in one’s person. Various strands of liberalism have stressed the freedom of the individual to choose ends, but security and material well-being, it is safe to say, emerge for liberals as baseline goods that any rational person is bound to desire. Thus, while in IR scholarship liberalism is frequently associated more with economic than with security relations, with low rather than high politics, in fact liberalism has from the start been concerned with security, albeit the security of individuals.

Liberalism cannot be understood apart from its normative commitment to individualism. The tradition insists that all persons deserve, and it evaluates institutions according to how far they help individuals achieve these goals. Liberalism can produce positivistic or causal theories of international relations, but its motivation – what makes its positivistic analysis worthwhile to liberal scholars – is its particular commitment to individual security. Furthermore, the liberal tradition has insisted that progress – understood in liberal terms, as increases in individual autonomy across societies – is possible in international life; for some liberals, indeed, macro-progress is inevitable, if not linear.

Liberalism and States

Nor is liberalism, considered broadly, anti-statist. Indeed, liberal theory has paid particular attention to the state as the institution defined by its ability to make individuals secure and aid their commodious living. Social contract theory, one of the leading underpinnings of the modern state and hence of the international system, arose from Enlightenment liberalism. But a consistent liberalism is not concerned with “state security” or “national security” except insofar as those are instrumental to the security of the individuals within those states. Liberalism is thus contrasted most often with – even defined in opposition to – realism. For liberalism, the state is a special institution owing to its coercive capacity. But contra realism, the state is not autonomous, as envisaged by realism, controlling the units of society; it is instead heteronomous, or subject to influence from individuals and the non-state groups they form, both within and without its national boundaries. Liberal theory does not depict the state as an independent actor manipulating and suppressing individuals and groups in service of its own ends. The implications for security studies are profound. Liberalism denies a single Staatsräson under which states perpetually seek relative power and are constrained only by relative weakness. Rather, states vary in their goals and methods, depending on which individuals, groups, and institutions constrain them.

Liberal international relations theory is best seen not as a deductive theory or a research program (Lakatos 1970) but as a paradigm (Kuhn 1960) or tradition (MacIntyre 1981; cf. Doyle 1997) that asserts that states are arenas of competition, subject to influence or capture by various societal actors. The actors that constrain the state, always reducible to individuals, may be domestic, international, or transnational. In recent years some have reformulated liberalism as a simple ‘inside-out’ theory that brackets not only the strategic interaction among states but also international institutions. The broad liberal tradition, however, is not so confined. Inasmuch as states are derivative, not primary, consistent liberalism refuses to grant state boundaries the privilege of segregating individuals in any deep or permanent way. Rather, individuals may form networks across states and cooperate to constrain or propel states. They may do so directly, through mobilization of various societal groups to pressure states, or indirectly, through the formulation of rules and institutions to bind states. Liberalism, in other words, resists allowing realism to reduce individuals to subjects or citizens of particular states; states are subject to influence, and so is the states system.

Liberalism’s individualism is obscured when liberal scholars in security studies adopt realist language in which states are the units of analysis. If the two traditions, realism and liberalism, are to be tested against one another, a common language must be adopted. That language could in principle be liberal, focusing on individuals and non-state actors; but because the institution in today’s world most responsible by far for security is the state, and realism’s unit of analysis is the state, liberals who study security typically adopt realism’s language and treat states as if they were actors. The question then becomes how far these “acting” states are constrained by domestic or international variables. Liberals typically say that states make war, trade, and so on, but they mean that groups, and behind those groups, individuals, use states to conduct these activities. Liberal claims about international security make little sense if not grounded in that general claim. (Some liberals are so dissatisfied with this privileging of realist categories that they are participating in a ‘human security’ literature that is, predictably, ignored by realists.)

Adopting realist or state-centric language allows liberalism’s distinctive claim about states and security to emerge. By treating state action as a function of individual beliefs and interests, liberalism effectively posits that, under broad conditions, states have a wider range of action than envisaged by realism. Indeed, as it relates to the study of security, liberalism’s most important claims are that states have meaningful choices and that their security varies with the choices they make. The foundation of this twofold liberal claim is that state actions are ultimately a function of the beliefs, interests, and interactions of the individuals that compose and influence them. The state is instrumental to the purposes of individuals. Individual influence on states and on security is mediated through groups and institutions within and across states. Individuals can create, sustain, and destroy institutions and thereby enhance or degrade national and international security.

Liberalism and the international system

Sustaining this claim requires some attention to feedback effects from other states and societies. Although liberal security literature that only examines individual states’ foreign policies may be guilty of slighting the role of international interaction, the general liberal claim is clear: the international system, under broad conditions, permits states choices. Holding constant international anarchy and the distribution of power, states A and B may pursue policy P1, issuing in international outcome O1, feeding back to A and B and leading them to repeat P1, reinforcing O1, and so on; or A and B may instead pursue policy P2, resulting in international outcome O2, which feeds back onto A and B and leads them to repeat P2, reinforcing O2, and so on. Whether O1 or O2 obtains depends upon who governs or influences A and B, what their interests and beliefs are, what sort of international institutions they have built.

In other words, for liberalism states can choose over time to create and sustain international conditions under which they will be more or less secure. To be sure, there are times and places in which state choice is heavily constrained and security is scarce, as during wartime. But liberalism maintains that such situations are ultimately contingent upon the properties of the states themselves. States’ freedom of action decreases when one or more of them are captured or influenced by actors whose interests or beliefs point them toward coercion of foreigners; their coercive tendencies compel other states to respond with coercion of their own, and the system itself becomes one in which insecurity feeds upon itself. Indeed, international systems rife with insecurity may feed back into states’ domestic properties, making it more likely that they will become authoritarian. For liberals, such extreme insecurity is not endemic to the international system. International anarchy does make cooperation among states more difficult because commitments are not guaranteed; but cooperation is possible and common as long as cooperative actors have sufficient influence over state policy. Liberalism’s qualified respect for the state is at once its strength and its weakness: it allows analysts to see how underdetermining is distribution of power in the international system; but it blinds them to the possibility that even liberal states and statesmen may be affected by and perpetuate Realpolitik.

Depicting states as if they have choices is analogous to normative liberal theory’s emphasis on individual choice. Normative liberal theory acknowledges that under some conditions individuals have few if any choices, but it seeks to increase individuals’ self-determination and asserts that such increases are possible over time. Just so, liberal IR theory looks to increases in states’ choices. Hence liberalism is more open than realism to applications of ethics to international relations.

Insofar as liberals seek to explain international relations, however, they must posit constraints or structures. Positivistic social science seeks to offer testable causal accounts of events, be they wars, alignments, or the end of enduring rivalries. Causal accounts entail conditional statements (if X, then Y), or a positing of structures. By definition, structures limit choices. Liberal IR theory locates them at the domestic and transnational levels. “Liberal democracies do not fight one another”; “authoritarian states tend to be revisionist”; “international institutions reduce transaction costs among states”; all of these statements are claims about the constraints of structures built by groups of individuals within, through, and across states. In this way, liberals do not rid analysis of structure and simply argue for agency. Rather, they shift structure from the international-systemic to the domestic or transnational level. States are constrained by domestic or transnational conditions to carry out policy P1 rather than P2.

In a sense, then, liberalism moves the agency problem from the international to the domestic level. Insofar as liberal IR theory incorporates sub-state actors, it does not necessarily depict them as free choosers either. Many liberal accounts of foreign policy refer to economic or parochial “interests,” implying that their material circumstances determine their policy preferences. Other accounts emphasize beliefs, but here too social science seeks conditions under which an actor is likely to choose one set of beliefs over another. Governments might be able to choose whether to build international institutions, or how to design them; but social science seeks conditions under which they will design them in one way rather than another. In other words, although liberal IR theory is certainly propelled by normative concerns for improving the conditions under which individuals live, insofar as it is meets realism on the latter’s positivistic grounds, it must try to reduce the scope of free choice for individuals. Thus the determination among many scholars to rid the theory of any “utopianism” or teleology (about which more below).

In security affairs, liberalism is known for its stubborn discrimination among states, especially according to domestic institutions or regime type. In general, liberal states – usually defined according to their institutions – are more rational than illiberal ones. Insofar as liberal states are attuned to this dynamic, they will be on their guard against illiberal states but relatively trusting of one another. Why, precisely, does liberal IR theory discriminate among types of states? Again, for liberals states are not autonomous, but rather mediate between individuals and political outcomes. If they mediate differently according to domestic regime, then liberal theory must draw distinctions according to regime. Domestic regimes that represent more individuals’ preferences will be different from those that represent fewer individuals’ preferences; those that require central decision makers to clear more veto points, from those with fewer; those that reveal preferences and capabilities, from those that do not; those with more commercial or pacific preferences, from those with more mercantilist or bellicose ones.

Relation to Other “Isms”

One way to clarify what liberalism says about security is to compare it to traditions and theoretical families other than realism. A third tradition in IR theory has been Marxism (Gilpin 1987; Doyle 1997). In its original form Marxism, like liberalism, does not take states as its primitive units. Marxism grants that privilege to economic classes, stretching across states. In the capitalist epoch, the owners or bourgeoisie and the workers or proletariat exist across countries simultaneously. The struggle between these classes is what drives politics. For Marxism, liberalism obscures the class struggle and is an ideology of the bourgeoisie, a story that helps perpetuate their domination. It functions to stifle the class consciousness of the proletariat by perpetuating the view that there are no classes in society because everyone is essentially the same. Although Marx was a revolutionary, the tradition has from the start had a strong reformist or social democratic tradition that in practice is politically if not theoretically liberal. Over the decades Marxian theory has paid greater attention to the state. As concerns security, however, the fundamental Marxist claim has been that the well-being of the proletariat depends upon its ownership of the means of production. The most famous claims have been those of Hilferding (1981) [1910], Luxemburg (1951), Bukharin (1972), and Lenin (1996) in the early twentieth century, to the effect that capitalism eventually produces imperialism and war. In today’s IR language, security is achieved through socialism, or the rule of the working class. The contradiction with liberalism, which is constituted in part by capitalism, is clear.

Liberalism and idealism (and utopianism) are sometimes conflated, particularly by realists seeking to discredit non-realist accounts (Carr 1946; Morgenthau 1948). In international relations idealism is best defined as the conviction that progress is possible – for some idealists, inevitable – in international life. “Progress” implies a movement toward a particular end preferable to the status quo. Idealism is hence teleological and at odds with modern social science, which insists on mechanistic or dysteleological accounts of social phenomena. Liberalism’s traditional emphasis on choice makes it seem idealistic, and no doubt many researchers are idealists in this liberal-progressive sense. But, as seen in a later section, liberal IR theory is at pains not to imply that people can simply choose cooperation or peace; it offers conditions under which they are likely to do so, and can be quite pessimistic about states that have irrational (illiberal) institutions. Still, inasmuch as liberalism asserts a universal rationality for persons, it retains a (minimal) theory of human nature and hence a teleology: if all persons share a rationality, and desire security and prosperity, then over time more and more individuals should learn how to achieve their goals.

Thus liberalism is often linked, via idealism, with the proposition that states are ultimately doomed and will give way to other, less coercive and divisive, political forms. The instrumentality of states in liberal thought implies this proposition: if individuals create states for their own ends, and retain control over those states, then they may weaken and dissolve states when it suits their ends as well. The functionalist literatures on interdependence and on European integration fit comfortably in the liberal tradition (see below), and thus one of the claims realists aim at liberals is that states are actually enduring, even strengthening. Thus liberalism cannot completely evade the accusation of idealism that realists have always hurled its way. The theory has a sort of teleology built into it, just as realism has a sort of dysteleology. Apart from a vague expectation that states will someday outlive their usefulness, however, liberal theory is not committed to their withering away at a particular time. Hence liberals studying security may in good conscience assume the indefinite perpetuation of the Westphalian states system. Nothing in liberalism’s logic, however, can explain the persistence of that system; liberalism does not predict any pressure that the states system might exert on individuals to perpetuate their particular state.

Liberalism’s relation to institutionalism, the family of theories that link international cooperation (and implicitly security) to international institutions, is sometimes hazy. Liberalism in IR is often taken to include only the domestic level of analysis or what Waltz (1959) calls the “second image,” and to exclude analysis of international institutions. This position is defensible, inasmuch as the early work of institutionalism’s leading theorist, Keohane (1984), implicitly accepts Waltz’s typology by bracketing states’ domestic properties and simply argued that the degree of institutionalization in the international system affects the degree of cooperation among states. Keohane theorizes little about conditions under which states will increase institutionalization; he accepts a realist account of how international institutions usually emerge – hegemonic stability theory (Gilpin 1981) – and argues that even after a hegemon fades states may continue to cooperate for mutual interest under institutions. Other institutionalists in like fashion leave exogenous states’ domestic properties, focusing instead on states’ preferences and strategic environments (Oye 1986; Stein 1993). This “third-image” strand of institutionalism, then, is not liberal according to the definition used in this essay.

Yet, liberals have historically emphasized international law and organization and seen them as efforts by individuals and groups across states – a “community of mankind,” as liberals have sometimes put it – to cooperate so as to constrain states. Indeed, international institutionalism is implied by liberalism’s refusal to grant states autonomy from sub-state actors. In liberal social contract theory, such actors overcome the inconveniences or pathologies of the state of nature by institutionalizing their relations: setting up a sovereign and a constitution governing their relations with that sovereign. What goes for individuals within a state goes for individuals across states. They may use the states they influence or capture, or reach across state boundaries, to institutionalize relations as well; they may create conditions under which states will be more cooperative to their mutual benefit. International institutions are supposed by liberals to have feedback effects, deepening cooperation among states. Institutions are another tool by which individuals influence states. In short, it is a truncated liberalism that ignores international regimes and looks only to domestic phenomena to explain international outcomes. Precisely because it refuses to allow states to separate individuals and groups in any deep way, it allows individuals and groups to cooperate across states for mutual benefit.

Liberalism’s fundamental individualism links it to rational-choice theory or rationalism, a hallmark of which is methodological individualism (Elster 1989). In the hands of IR theorists, rationalism has become flexible enough to use states as its units of analysis; much realism (Fearon 1995; Kydd 1997; Copeland 2000) is rationalist. But because rationalism’s roots are in individualism and utilitarianism, it is more consistent with liberalism, which refuses to grant states autonomy or agency. Liberalism also ascribes to individuals a universal (if minimal) rationality. Individuals generally want security and prosperity and, in proportion to how well they understand how the world works, will seek those ends as efficiently as possible. People who seek other ends – martial glory, martyrdom, material self-denial – are, for liberalism, irrational. As recounted in a later section, much recent liberal work on security is rationalist: individuals act according to Zweckrationalität, seeking to maximize expected utility, have transitive preferences, and so on. Liberal analysis that adopts realist language about states uses game theory to analyze the effects of preferences changes on international outcomes.

But some liberal IR work is better described as constructivist. The core of constructivism, or its essential difference with rationalism, has occasioned much controversy (Fearon and Wendt 2002; Dessler and Owen 2005). If constructivism is constituted by holism, or an emphasis on social wholes over parts, then it does not overlap with liberalism; thus constructivism that stresses cultural particularity over universal rationality is not liberal. But if constructivism is constituted by the notion that ideas (beliefs, preferences) matter (Klotz 1995; Price 1997); or that actors proceed according to Wertrationalität or a logic of appropriateness (March and Olsen 1998); or that individual agents can combine to alter social structures and international outcomes (Bukovansky 2002; Crawford 2002; Finnemore 2003), then much constructivist work is liberal. That liberalism spans the rationalist-constructivist divide does not make it any less coherent than rationalism for spanning the liberal-realist divide.

An essay on liberalism and security must face squarely that much, perhaps most, liberal IR literature concerns low politics or international political economy rather than international security or high politics. That skew might lead to the impression that liberalism has little to say about security, apart from claiming that democracies do not fight wars against one another. But inasmuch as it asserts that liberal states are more rational, liberalism does implicate security. For, as elaborated above, liberalism at least implies a universal substantive rationality for each individual of commodious self-preservation. Rational institutions – domestic and international – are those that help secure that end most efficiently. Liberal IR literature’s bias toward heavily institutionalized phenomena discloses its assumption that less institutionalized relations are less secure. Liberals routinely insist that their mechanisms could apply to security affairs, but too seldom carry out such applications. By the same token, however, an essay on realism and security would need to address why realist literature has the opposite bias, namely slighting low politics, implicitly acknowledging that liberals are right that institutionalization implies cooperation. In any case, nothing in the logic of liberalism implies that liberalism has less to say about high politics than about low. Liberalism does not require a de-emphasis on security. Rather, its limited respect for states requires it to doubt realism’s insistence that states must worry about security vis-à-vis all other states at all times.



The assertion that all individuals across time and space are essentially the same is itself far from universal, but its provenance is ancient. In late Western antiquity, Christianity and Stoicism alike asserted, against the typical classical separation of men into civilized and barbarian, that all men shared an essential property (Kohn 1946). This essential similarity did not carry an implication of equal rights – Stoics and early Christians were not liberal – but did imply a sort of cosmopolitanism that anticipates liberalism’s ambivalence toward the sovereign state system that later was to emerge. In medieval Europe, Christian thinkers agreed that the essential similarity of all men implied that all should live under a single monarchy, as in the ancient Roman Empire. The chief difference among writers was whether the monarch should be the Holy Roman Emperor (wrote Dante Alighieri in 1313), the Pope (wrote Giles of Rome in 1302), or the King of France (wrote Pierre Dubois in 1306). Dante’s argument is proto-liberal in its assertion that the right political institutions will allow the fullest possible human development.

The Renaissance and Reformation continued the assertion of Christian universalism, and the Reformation in particular was proto-liberal in asserting the individual’s right to interpret the Bible for him- or herself. But the norm of a united Christendom began to crumble under the onslaught of secular arguments justifying the sovereignty of a particular prince or people. Niccolò Machiavelli (1998) [1532] provides a top-down version, quintessentially realist: the Prince, an ambitious warrior, constructs by force the state, which effectively becomes impersonal and operates according to its own amoral (or immoral) logic (Mansfield 1983). Jean Bodin (1992) argues for a strong view of state sovereignty consistent with the descriptive claims of realism.

Security and the Social Contract

Modern liberalism was born with the alternative, bottom-up stories told by such writers as Thomas Hobbes (1968) [1660], Benedict Spinoza (2007) [1670], John Locke (1988), [1689] Jean-Jacques Rousseau (1999) [1754], and Immanuel Kant (1983) [1795]. For these the state was, in principle if not historically, constructed by individuals to serve their joint ends: they found life without a central coercive power sufficiently costly that they set up a sovereign. Social contract theory elevated the individual, regardless of birth or wealth, to equal political status.

Not all Enlightenment thinkers ended up liberal in the IR sense. Indeed, balance-of-power theory was in a sense the new Newtonian mechanics applied to relations among states (Knutsen 1997); Boucoyannis (2007) goes so far as to say that balance-of-power theory is liberal, not realist. In any case, some social contractarians end up realist by making the state effectively unaccountable to the individuals who created it. Hobbes and Rousseau allow the state the greatest autonomy. For Hobbes, individual subjects give up nearly all rights to the sovereign they construct; for Rousseau, the General Will subsumes all individual wills. As individuals cease to influence the state once they have constructed it, it is no surprise that these writers depict a dangerous international realm. For Hobbes, sovereigns confront one another in a state of nature analogous to that among individuals prior to the social contract. For Rousseau, the international situation is a state of war; peace is only possible if states have as little to do with one another as possible. Notwithstanding their starting position as individualists, these canonical thinkers are realists.

By contrast, Locke and Kant limit the power of the sovereign by holding it accountable to the subjects or citizens. Locke goes so far as to allow the subjects the right of revolution if they judge that the sovereign has violated the social contract. Kant rejects revolution, but does require the executive to seek society’s approval, expressed through a duly elected legislature, before declaring war. Locke wrote little about international politics, but is well known for arguing that a conqueror is bound by natural law to respect the rights of the conquered and hold harmless subjects of a conquered land who played no part in the war (Locke 1988:384–97). Kant’s theorizing on international relations is among the best developed of all lumières, and it is he who, more than anyone, sets the terms on how liberalism and security relate. He sees that, if individuals are to enjoy their rights and develop morally, international politics must be set right just as national politics. States are real and coercive, but vary descriptively according to whether they are republics, accountable to law and constrained by citizens, or despotisms, arbitrarily ruled. (A republic, for Kant, is not a democracy, which is the one form of government bound to be despotic owing to its having no one left to constrain the sovereign. Republics may be governed by a monarch or aristocracy.) Republics, being law-governed, will seek to have their relations with one another law-governed as well, so as to escape the state of war that obtains in international life. They will avoid war with one another and will expand commercial ties. And their number will increase gradually, as more and more despotisms will see republican success and demand republican government (Doyle 1983; Huntley 1996).

Kant is not alone among late eighteenth- and early nineteenth-century Enlightenment thinkers in linking liberal institutions to international security. Such arguments are common among the French philosophes, British Enlightenment figures such as Adam Smith, Jeremy Bentham, and David Ricardo, and American figures such as Tom Paine, Thomas Jefferson, and James Madison (Howard 1978; Zacher and Matthew 1995; Walker 2000). Particularly common are claims about the virtues of free commerce, linked to republics, over mercantilism, linked to despotisms: allowing individuals and firms to conduct business freely across national borders as within them would allow a natural harmony of interests among individuals to emerge. Now Enlightenment mechanics were being applied not to states but to individuals across states. States were distinguished according to whether they allowed their subjects – or, in republics, their citizens – this commercial freedom. The Manchester School in England pushed this claim further: Richard Cobden, John Bright, and others argued that war and imperialism were caused by states’ control of the distribution of material resources; if states allowed markets to work, all people, in the colonizing as well as colonized worlds, would be better off. For these classical liberals, states mattered in the sense that they could suffocate individuals and civil society, or else get out of the way. (It is worth noting, however, that Victorian liberals were ambivalent about the state: they were nationalists, favoring the fragmentation of the human race into nations, owing to their anti-imperialism; empires were the true enemy of liberty, and nationalism was the first line of attack against empires; liberal nation-states would achieve peaceful relations [Hobsbawm 1990].)

Liberals, particularly in the Anglo-American world, continued their writing and theorizing in the early twentieth century. John Hobson (1902) attributes imperialism to domestic institutions that empower investors and militaries at the expense of the average citizen. Norman Angell – frequently mocked, seldom read – argues that war was irrational among commercial states, a throwback to the old aristocratic age (Angell 1910). Most consequential was Woodrow Wilson, a prominent American political scientist who became President and attempted to use American power during and after World War I to jolt the world into Kantianism. The peoples of the world have common interests and should determine for themselves the power under which they live. The horrific war was caused by the “balance of power,” a term covering self-aggrandizement by great powers ruled by monarchs and aristocrats who were laws unto themselves. Respecting the rights of man would dissolve war-making empires and set up in their place a law-governed international society.

In the 1920s liberal ideas about states and international relations were ascendant but not triumphant. Crucial to the debate were competing theories of the state. Harold Laski argues against Bodin’s “monistic state,” insisting that the “pluralistic state” was descriptively more accurate (and normatively preferable). The pluralistic state is non-hierarchical, and is moreover just one of many pluralistic institutions in society, such as labor unions and religious groups. Sovereignty, then, is “neither indivisible nor supreme” (Schmidt 1998:165). In Germany Carl Schmitt (1976) roundly rejected this liberal notion of the state, in part for its implications for international relations. Liberal depictions of the state are wrong: states are autonomous, with the sole power to commit the essential political act of naming the enemy. In fact, argues Schmitt, liberal states are using such arguments to perpetuate their domination of the world. The League of Nations is simply power politics in a liberal disguise, a savvy effort by the powerful war victors to suppress the losers. Such arguments gained a worried hearing in the Anglo-American world. Carr’s (1940) famous broadside against liberalism calls it dangerous for its refusal to acknowledge the claims of Germany and other rising powers. Niebuhr (1944) and Morgenthau (1948) accuse liberals of moralism, confusing their own interests and morality with those of the world. Herz’s security dilemma (1950) locates international conflict in the situation in which states find themselves.

The dominant narrative in IR historiography is that realism routed liberalism after World War II and liberalism had little to say about security. Waltz’s (1959) argument in favor of “third-image” or situational theory, borrowed from Rousseau, is taken to have discredited liberalism as a source of hypotheses on security. In fact, liberal scholars continued to challenge realism in the 1950s and 1960s. Some continued to argue for conceiving the units of world politics as individuals rather than states (Dunn 1950). Some focused on realism’s insistence that all states were fundamentally the same regardless of domestic properties, and argue in favor of liberalism’s assertion that states differ according to which domestic actors influence or control them. Wolfers (1951) notes that in practice realists assume that different states have different ends, thereby implying that there is not a single logic of foreign policy; Wolfers even outlines a theory of state ends. The realist emphasis on making IR a science by evacuating all teleology from it led scholars to turn to natural sciences and engineering for approaches. Thus systems theory, with its scientific bona fides, became ascendant; yet, ironically, liberal hypotheses surfaced in the systems theories of the 1950s and 1960s. Kaplan (1957), Rosecrance (1963), and Hoffmann (1965) all include state-level characteristics in the international system.

Liberalism’s focus on increasing security via international law and organization continued as well. The journal International Organization, founded in 1947 by the World Peace Foundation, was a forum for liberal scholarship of this type. Much of it was descriptive, much legal and normative; but some scholars made causal claims that contradicted those of realism – for example, that international organizations are increasingly eroding the predominance of states in favor of a world community of individuals (Rothwell 1949). Others challenge the realist claim that balances of power form spontaneously in the international system, and argue for the historical liberal claim that peace – particularly in the nuclear age – require positive action by countries in the form of international organizations and collective security (Claude 1964). These liberals are not blithely ignorant of states, power, and the arguments on their behalf; but they doubt the descriptive and normative adequacy of realism.

Above we discussed liberalism’s functionalism: states emerge because they serve the purposes of (at least some) individuals, and it follows that they will fade if they cease to serve the purposes of (at least some) individuals; states are not permanently self-perpetuating. Most postwar liberal scholars make no strong claims that states are withering away. But some do make such functionalist arguments, following Mitrany (1965). Two world wars and the threat of nuclear annihilation showed that states as institutions, and hence the states system, had outlived their usefulness. European integration, begun in 1950, contributed empirical support. Deutsch (1957) and E. Haas (1958) are among the functionalists making these arguments. The implications for security are profound: states, once guarantors of individual self-preservation, are now the chief threat to it, and once they were gone individuals would be more secure.

Functionalists and neo-functionalists emphasize interdependence among societies, a familiar liberal mechanism for peace and cooperation. At this time realists continued to respond that liberals failed to appreciate the ability of states to override any constraints from interdependence. One important liberal response was to posit realism and liberalism as ideal-typical depictions of the international system, and to argue that in some times and places the situation was closer to realism, in others, to liberalism. Keohane and Nye (1977) operate at the level of the international system, Rosecrance (1986) at the state level; but common to both are a recognition of the continuing conditional validity of realism and a simultaneous insistence that ties across societies – particularly via transnational corporations, banks, and other economic actors – can make states and bilateral relations more secure than realism allows.

The Neo-Theories

The reverberations from Waltz’s 1979 bombshell are still felt in the study of international security. Theory of International Politics was a clarifying moment in security studies; its powerful arguments for a minimalist structural theory altered the terms of debate across the subfield. Waltz convinced many that liberalism could not offer a theory of international politics. Liberal hypotheses about differences among states were reductionist, neglecting the emergent properties at the level of the international system. Liberal hypotheses about interdependence bloated the international system with complications of insufficient scientific merit. In the 1980s, scholars who resisted neorealism’s pessimism – the best we could hope for was the stable bipolar international system that we had – accepted the argument that explanation must focus on the international-systemic level. Liberal research focusing on domestic determinants of foreign policy certainly continued (e.g., George et al. 1980; Shapiro and Page 1988). Yet the most important arguments were now over what variables belonged in a systemic theory: process? institutions? technology? norms?

The most influential response was Keohane’s functional theory of institutions (1984), which followed the neorealist assumption that states are unitary rational actors and argued that even under anarchy they may cooperate – with obvious implications for international security – if their relations are institutionalized. International institutions increase the information available to states and thereby reduce transaction costs and incentives to defect from agreements. So-called neoliberals use game-theoretic logic to demonstrate that states in an anarchical system could cooperate depending upon the incentives and the strategies they chose (Axelrod 1984; Oye 1986). Neoliberalism (later institutionalism) follows neorealism in abstracting from domestic properties and treating states as unitary rational actors (Baldwin 1993), and hence on its own terms departs from the liberal tradition. It belongs instead to the tradition running from St.-Pierre through Hedley Bull that sees possibilities for states, regardless of domestic regime type, as sharing interests in peace and cooperation and as sufficiently rational to create and sustain conditions to achieve those interests. Realists, however, were not convinced by neoliberal logic. They focused during these years on the latter’s assumption that states seek absolute rather than relevant gains (Grieco 1990).

Liberalism was lurking in the shadows of the “neo-neo” debate. What type of gains states seek is a state-level problem, one that neorealists and neoliberals had rendered empirically insoluble under the debate’s ground rules. Liberalism, of course, had always had a general answer: states whose domestic institutions constrain them to seek the general welfare will seek absolute gains, all else being equal. And in the event, neoliberals usually ended up studying relations among advanced industrial democracies, which are relatively cooperative if not harmonious. While cautioning that international cooperation can be exploitative and exclusionary – that cooperation per se is not a moral good – they have overwhelmingly emphasized cooperation to improve human welfare. Their case studies tend to contain material about societal pressures toward international cooperation. Keohane even raises the question of whether transparent states might get along better because they add information to the environment (1984:258–9). At the same time, neorealists emphasized relations between democracies and non-democracies or simply among non-democracies.

Current Debates

The Democratic Peace and its Progeny

Thus the gate was always ajar for liberalism to return from its brief exile from security studies. It was the democratic or liberal peace thesis that pushed the gate open. There are actually two democratic peace theses: the dyadic, widely accepted, is that liberal democracies do not fight wars against one another; the monadic, more controversial, is that liberal democracies are generally more pacific toward all types of states (Rummel 1979). These claims were familiar in the liberal tradition, and Doyle, an early articulator of the thesis, looked to Kant as the theoretical source (Doyle 1983). What gave the thesis life was the empirical claim that in fact democracies do not fight one another (ibid.), even when variables such as trade, geographical propinquity, alliances, and the distribution of power are controlled for (Maoz and Russett 1992; Bremer 1993; Thompson and Tucker 1997). The dyadic thesis has been challenged empirically (Gowa 1999; Gartzke 2000) and the logic has been attacked (Layne 1994; Rosato 2003), but it is fair to say that a consensus exists among IR scholars that there is a democratic peace. The democratic peace currently poses the greatest empirical challenge to realism’s predominance in the security subfield.

No such consensus exists, however, as to why liberal democracies exhibit this peculiar behavior. In the 1990s some scholars pitted ideas against institutions. It was liberal-democratic norms either of compromise or of material well-being that kept these countries at peace with one another, or it was the constraints their domestic institutions placed upon their chief executives (Maoz and Russett 1993). Other scholars combined ideas and institutions, seeing them as derived from the same liberal source (Doyle 1997; Owen 1997). More recently, the democratic peace has become a proving ground for the newest divide in IR, rationalism versus constructivism (about which more below). Rationalists begin with the premise that war is always irrational ex post facto: both winner and loser would have been better off with the same proportional settlement without having borne the costs of the war. So wars result from failures of commitment or information (Fearon 1995). One rationalist mechanism for the democratic peace is that democratic leaders face higher domestic political or “audience” costs for backing down in a crisis, and so other countries take care not to push them too far (Fearon 1994). Another is that democracies are more transparent, allowing other states to assess their capabilities and intentions more and reducing the probability of misjudgment (Schultz 1999). Bueno de Mesquita et al. (1999) argue that democratic leaders, being more vulnerable to ouster from losing a war, tend to devote more resources to winning, making them less attractive targets. Lipson (2003) has combined these and other rationalist mechanisms into a general claim that democracies bargain more efficiently and are more reliable partners. Meanwhile, constructivists have fleshed out ideational explanations. The citizens of liberal democracies form an expanding transnational community of shared values and are gradually pacifying relations among societies (Risse-Kappen 1994; Kahl 1999; Williams 2001; Harrison 2004). Some have offered constructivist mechanisms for the expansion of the zone of peace (Huntley 1996; Cederman 2001).

Whatever the causes, research into democratic peace has opened up a larger research program on democratic advantages in international relations. Lake (1992) argues that democracies not only avoid war with one another but also tend to win the wars they fight. Bueno de Mesquita et al. (1999), Reed and Clark (2000), and Gelpi and Griesdorf (2001) find that they select easier wars; Reiter and Stam (2002) concur and add that democratic citizens make better soldiers. (These findings are in marked contrast to the classical realist assertions about democracies found in Tocqueville, Kennan, Lippmann, and others that democracies are reckless about using force and generally ill-equipped for the jungle law of international relations.) Russett and Oneal (2001) have reassembled three legs of the liberal tradition into a self-reinforcing “Kantian Triangle”: democracies, they argue, are less likely to fight one another, more likely to be members of international organizations, and more likely to be interdependent; and these three tendencies feed back onto one another, meaning that democracies are in a virtuous cycle of interaction. Ironically, these democratic advantages, argue some, have been exploited by the United States to perpetuate its hegemony (Ikenberry 2001; Owen 2001/2); liberalism, as it were, is in the service of realism.

Other Research Areas

Various venerable liberal claims about international security continue to inspire research. Much recent empirical work supports the proposition that economic interdependence, under broad conditions, promotes peace (Oneal and Russett 1997; Gartzke et al. 2001; for a survey see Mansfield and Pollins 2001). M. Haas (2005) argues against realism that ideology is a cause of conflict and of cooperation among states. More broadly, the recently growing literature on domestic and transnational ideas and IR fits comfortably within the liberal tradition. Studies of transnational advocacy networks (Klotz 1995; Keck and Sikkink 1998; Finnemore 2003), particularly as they focus on human rights, do implicate the original liberal concern with individual security. Some scholarship has noted that human rights advocates can actually alter the security strategies of states (Peceny 1999; Walldorf 2008). Most directly concerned with mainstream security concerns have been works that argue for a role in transnational networks in ending the Cold War (Risse-Kappen 1994; Evangelista 1999; Thomas 2001). Legro and Moravcsik (1999) have argued for another sign of liberalism’s late success in security studies: many scholars who believe they are good realists – in particular, the neoclassical realists (Rose 1998) – are actually liberal, allowing state preferences to vary with domestic variables rather than solely with the distribution of power across the international system.

Reformulations and Meta-Theory

Concurrent with these empirical studies have been developments in how liberal IR theory is formulated. One question that sometimes arises, especially at academic conferences, is whether liberalism itself has been superseded. One version of this claim is that rationalism has subsumed liberalism (and realism). Another is that the “first debate” between liberalism and realism has been superseded by the “third debate” between rationalism and constructivism.

As alluded to above, the relation of liberalism to rationalism is complex. Rationalism as social theory has the same origins as liberalism: Hobbes was doing “social physics” in which individuals were matter in motion. Liberalism produced utilitarianism, the social philosophy of classical and neoclassical economics and hence of rationalchoice theory. These common roots are evident today in the entangling of liberal and rationalist research. Insofar as rationalists recognize differences in state preferences, domestic constraints, or abilities to reveal information, they adopt longstanding liberal assumptions about international security.

One prominent rationalist-liberal approach is two-level games (Putnam 1988; Milner 1997; Gaubatz 1999), which take as the rational chooser the central decision maker and include in the strategic environment both external (other states) and internal (society, interest groups, a legislature, and so on). A two-level game is in a sense a hybrid of realism and liberalism; but inasmuch as realism tends to elide domestic constraints while liberalism recognizes foreign constraints, the approach is more consistent with liberalism. Relatively little two-level game analysis has been done in security agreements, although the abstract framework itself is equally applicable to security as to IPE. Another prominent rationalist approach directly applied to security is that of Bueno de Mesquita and his colleagues (1999). They argue that a central decision maker faces different domestic incentives toward the use of force, alliances, and so on, depending upon the size of the “selectorate,” or the entity to which it is accountable. Finally, the ambitious “strategic choice” framework of Lake and Powell (1999) is fundamentally liberal, in that it is open to crossing levels of analysis and positing individuals as decision makers.

Rationalism and liberalism, however, merely overlap; they are not identical. Much rationalist research and theorizing in security takes unitary states rather than individuals as units of analysis. Neorealist rationalist work includes that of Copeland (2000), Kydd (1997), Fearon (1995); liberal rationalist work includes that of Powell (1993), Fearon (1994), Milner (1997), and Schultz (1999). Liberalism, for its part, contains theories and propositions concerning the ideas – beliefs, preferences, norms, and so on – of individuals and the institutions they construct. As such, liberalism crosses into constructivism.

Among constructivist work in security that fits in the liberal tradition is that of Legro (2005), who offers a theory of foreign-policy ideational change. A great deal of constructivist work – Price 1997, Keck and Sikkink 1998, Crawford 2002, Finnemore 2003 – looks to the transnational level, which would please nineteenth century liberals in particular. Of course, much liberal work on norms – namely, institutionalism – treats norms as instrumental to actors’ exogenous ends, and is hence rationalist. Nothing in liberalism, however, precludes actors’ following a logic of appropriateness. Similarly, constructivism’s holism (Fearon and Wendt 2002) might seem fundamentally anti-liberal. But insofar as constructivism attempts to account for normative change by appealing to ideational entrepreneurs (Checkel 1997; Crawford 2002; Finnemore 2003; Dessler and Owen 2005), it would seem to require liberalism. Yet, here too, not all constructivist work is liberal. Wendt (1999) takes pains to leave domestic properties out of his theory of international norms. In sum, it is a mistake to pit liberalism against rationalism or constructivism. Liberalism is defined in opposition to realism and Marxism; like those, it cuts across the rationalist-constructivist divide.

Moravcsik’s (1997) reformulation of liberal IR theory says as much. Liberalism, for Moravcsik, comes in ideational, commercial, and republican varieties, with the first being constructivist and the others rationalist. Moravcsik’s reformulation is most notable for its distilling from the liberal tradition a coherent social-scientific research program. Liberalism assumes, in contrast to realism, that states’ preferences form prior to interaction with other states and are a function of the interests and influence of various domestic and transnational groups. Reformulated liberalism, then, follows in the mainstream tradition of conceding to realism state-centric language but insisting that states are heteronomous rather than autonomous: what they do is shaped by their domestic properties, which reduce to individuals within and across states. The reformulation, however, deliberately departs from the liberal tradition in its determined elimination of any teleology. Whereas liberalism has traditionally assumed, and indeed been motivated by, the premise that all individuals have an interest in commodious self-preservation, Moravcsik leaves open what individual preferences will be. Thus no movement or progress in history is assumed. It also departs from the tradition by excluding any influence that international institutions might have upon state preferences. In the Kantian and Wilsonian understanding, international institutions are created and sustained by governments acting at the behest of their citizens; institutions are one of several tools individuals have at their disposal. Thus it is perfectly liberal to acknowledge that they can alter states’ tactics, strategies, and even ends. Eliminating this feedback loop handicaps liberalism’s explanatory power.

Where From Here?

Liberalism as a tradition in security studies continues to enjoy successes as it has since its emergence during the Enlightenment. Its most striking recent successes concern the democratic peace and related research on democratic advantages in international cooperation. Liberalism is a useful guide to international security insofar as individuals and the groups they organize affect or, at a maximum, erode states. In a world where increasingly efficient communication technologies continue to allow private individuals and groups to mobilize independent of states, liberalism will continue to be a useful approach to security. Liberalism’s power will be limited insofar as states are autonomous, able to conduct their business unconstrained by domestic and transnational societies.

Far from superseding liberalism, rationalism and constructivism perpetuate the tradition. No doubt, recent trends in security scholarship in the liberal tradition will continue into the near future. In terms of substance, more work is to be done on the distinctiveness of democracies. In particular, a cluster of propositions that has emerged – the democratic peace, democracies’ martial prowess, their heightened interdependence and ability to cooperate – suggests that democracies enjoy an advantage in international anarchy, including in the security realm. All else being equal, we should expect a macro-trend toward more and more democracies (Doyle 1983; Huntington 1993; Cederman and Gleditsch 2004). As is sometimes noted, this proposition is striking in its contrast with periods when liberal democracy appeared a handicap, particularly in the 1930s. The specter of teleology now reappears: perhaps nature is pulling the human race in a particular direction after all? One line of research that begs for attention is whether this selection effect in favor of liberal democracy is conditional, in either the short or the long term. Realism has at least one counter-proposal: any selection effect is a function of American hegemony, as the United States confers many advantages to states that liberalize and democratize; indeed, America has directly promoted liberal democracy in much of the world for several decades. If American hegemony truly is eroding at last (Zakaria 2008), then we would expect the democratic advantage to erode with it. Liberal IR theory would counter that political and economic liberalism flourishes because it so clearly increases societal welfare, including individual security, and states are under pressure to adopt it.

Related, the question of whether liberalism may offer a systemic IR theory – one distinct from that of realism, to be sure – bears elaboration and investigation (Moravcsik 2008). Liberalism is not simply an argument that states are influenced by domestic actors. Its focus on individuals and the groups they construct equips it well to illumine transnational networks. Ideas diffuse, and with them preferences; transnational networks flourish; demonstration effects across states suggest that feedback loops connect people without regard to nationality (with a few remaining exceptions). These phenomena may affect states’ security policies and ultimately the security of people. More theorizing and empirical work is needed.

That said, liberalism would also do well to turn more attention to transnational networks whose goals are not progressive in the liberal sense. Some of the most consequential transnational groups in the twenty-first century thus far have been radical Islamist ones. These are animated by ideas about the good society, attempt to influence and capture states, and have prodded the world’s most powerful state to move its policies down a much more costly path. Liberalism is conceptually equipped to explain these groups and their effects. Yet, the history of liberal research in security shows that liberals themselves are disinclined to study “bad” or illiberal ideas and institutions. This may be for theoretical reasons: liberalism’s emphasis on individual rationality and rights renders atavistic and mysterious people who seek not commodious self-preservation but martyrdom, not a prosperous society but the restoration of a religious empire. It may be for psychological reasons: those scholars who reject realism may do so because they reject pessimism. Whatever the reason, leaving war and violence to the realists has always been a liberal temptation. Perhaps this time, with non-state networks causing so much insecurity, liberalism can resist the temptation.


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  • Stein, A.A. (1993) Why Nations Cooperate: Circumstance and Choice in International Relations. Ithaca, NY: Cornell University Press.
  • Thomas, D.C. (2001) The Helsinki Effect: International Norms, Human Rights, and the Demise of Communism. Princeton: Princeton University Press.
  • Thompson, W.R., and Tucker, R. (1997) A Tale of Two Democratic Peace Critiques. Journal of Conflict Resolution 41, 428–54.
  • Walker, T.C. (2000) The Forgotten Prophet: Tom Paine’s Cosmopolitanism and International Relations. International Studies Quarterly 44, 51–72.
  • Walldorf, C.W. (2008) Just Politics: Human Rights and the Foreign Policy of Great Powers. Ithaca, NY: Cornell University Press.
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  • Wolfers, A. (1951) The Pole of Power and the Pole of Indifference. World Politics 4, 39–63.
  • Zacher, M., and Matthew, R. (1995) Liberal International Theory: Common Threads, Divergent Strands. In C.W. Kegley (ed.) Controversies in International Relations Theory: Realism and the Neoliberal Challenge. New York: St. Martin’s Press, pp. 107–50.
  • Zakaria, F. (2008) The Post-American World. New York: W.W. Norton.

Links to Digital Materials

Kant on the Web. At∼ppp/Kant.html, accessed May 8, 2009. A good source on the most influential and comprehensive early liberal thinker on international relations. The site covers Kant’s works on metaphysics, epistemology, and ethics as well. It is maintained by Steve Palmquist of Hong Kong Baptist University.

Manchester School. At http:/, accessed May 8, 2009. Provides links relating to the nineteenth-century British free-trade movement. Many arguments in liberal IR work today have their origin in Manchester School figures such as John Bright, Richard Cobden, and Walter Bagehot. Maintained by the History of Economic Thought at New School University.

Democratic Peace Blog. At http:/, accessed May 8, 2009. Freedom, Democracy, Peace; Power, Democide, and War. At http:/, accessed May 8, 2009. Two websites – the first a blog – maintained by R.J. Rummel, a pioneer of the contemporary empirical study of the democratic peace. Rummel includes much material on the democratic peace, as well as on his “democide” research program, which links lethality in civil conflict to non-liberal state structures.

The Human Security Report Project. At, accessed May 8, 2009. In its own words, “The HSRP conducts research on global and regional trends in political violence, their causes and consequences and presents its findings in a manner that is accessible to the policy and research communities, the media, educators and the interested public.” Maintained by the School for International Studies at Simon Fraser University in Vancouver, British Columbia, Canada.

The Correlates of War Project., accessed May 8, 2009/. The well-known quantitative initiative contains datasets useful for testing liberal hypotheses, including international trade, membership in international governmental associations, and governance changes. Maintained by Paul Diehl at the University of Illinois.