In international relations, there is no sheriff, no impartial judge, and no universally recognized social contract—only states. Some are strong, many are weak, and all navigate a system indifferent to liberty or restraint. This anarchic condition is the real-world arena in which nations rise and fall. Here, libertarian theory, coherent in domestic affairs, encounters a hard contradiction.

Critics often see realism and libertarianism as opposites—one focused on state survival, the other on individual liberty. Unified libertarian theory (ULT) sees them as structurally similar, positing that they are in fact complementary. ULT acknowledges that the nonaggression principle (NAP) cannot operate the same way in international politics. The world, at the international level, lacks the legal scaffolding required for rights enforcement and reciprocal restraint. ULT insists that states rely on deterrence, alliances, and proportional force, while holding fast to the moral code to preserve liberty.

ULT reframes the ethics of foreign and domestic policy not as a contradiction but as an adaptation to different enforcement environments. Liberty thrives where institutions ensure reciprocity; where they cannot, the same ethic must take a strategic form. ULT is not a hybrid of opposites but a unified logic scaled to circumstance. It argues that both liberty at home and prudence abroad stem from a shared premise: power must be constrained, by strategy when necessary. Modern libertarians face a dilemma: their ideals demand peace, but reality requires strength. The issue is not whether the NAP can apply universally but where and how it applies. ULT contends that libertarianism is realism at the individual level. The divide lies not in values but in enforceability. Ultimately, ULT proposes that restraint, whether enforced by law or driven by strategy, is the foundation of stability. Liberty is preserved through moral clarity at home and operational realism abroad.

Institutionalizing the Nonaggression Principle

Libertarian domestic theory begins with a moral assumption: individuals possess inherent rights—chiefly, the rights to life, liberty, and especially, property. Additionally, coercive force must be strictly limited to defensive purposes. This ethical claim does not emerge from contemporary abstraction but a long philosophical lineage stretching back to John Locke (1988, 6), who famously argued in Two Treatises of Government that “being all equal and independent, no one ought to harm another in his life, health, liberty, or possessions.” In this classical liberal vision, freedom is not a grant from the state but a prepolitical condition that precedes and limits state authority.

To move from principle to practice, however, this moral axiom must be given institutional form. The NAP alone cannot resolve disputes or deter violations. It requires mechanisms, rules, courts, and enforcement tools capable of embodying its logic in real-world governance. The state, in this light, is an immoral actor, but it is a structural necessity, a framework within which liberty can survive contact with reality.

This is not to say that all institutions qualify. The libertarian view insists that legitimate institutions are those that constrain power, not amplify it. Courts must be bound by known laws, enforcement must be proportional and contestable, and legislation must respect the presumption of individual sovereignty. The state, properly conceived, is not a provider of virtue or equality but a referee whose sole job is to enforce the rules of nonaggression.

This distinction between liberty as moral theory and liberty as legal order is essential to understanding why libertarianism works domestically. It functions not because people are inherently cooperative but because coercion is costly, agreements are enforceable, and property is intelligible. Institutions do not create liberty, but they do allow it to persist.

Libertarianism in Domestic Governance

The natural question that follows is, How do institutions allow liberty to persist? In the context of a domestic polity—where contract enforcement, property boundaries, and norms of voluntary interaction are institutionally embedded—the NAP functions as a real and effective organizing rule. The limited domestic state, properly constrained, contains all the ingredients necessary to uphold liberty: a known body of laws, transparent mechanisms of redress, and decentralized enforcement. In such a system, initiating aggression is not merely immoral; it is illegitimate and punishable under general rules accessible to all.

Randy Barnett (1998), in his seminal work The Structure of Liberty: Justice and the Rule of Law, provides one of the institutional blueprints for building the legal architecture. His project begins not with moral declarations but practical challenges: the problems of knowledge, interest, and power. Any society that hopes to protect liberty must overcome these. To address them, Barnett argues that three types of institutions must exist: a system of legal rules that clearly define and protect rights, a neutral and decentralized mechanism for adjudicating disputes, and an enforcement apparatus that secures justice without becoming a source of arbitrary coercion. This model establishes conditions under which individuals can peacefully pursue their own. Judges and enforcers are accountable not to sovereign authority but to shared principles and, in competitive systems, to the pressures of reputation, ethics, and transparency.

Crucially, his system does not eliminate conflict; it channels it into nonviolent processes of redress and resolution. Rights violations become actionable, property claims contestable, and force, when used, constrained by procedure and proportionality. This vision of justice stands in sharp contrast to statist or collectivist models, which rely on discretionary command and central redistribution. Instead, Barnett’s framework is one of distributed power: legal norms emerge through voluntary interaction, contract, and community-derived expectations. Coercion is constrained not only by rules but by the structural design of the system itself. What makes this vision institutionally robust is its internal coherence. Legal rules are general and predictable, adjudication is independent and contestable, and enforcement is limited and based on consent. Together, these mechanisms transform the NAP from an ethical injunction into a functional doctrine of civil order. They create a society where conflict is managed without domination and cooperation occurs without compulsion.

Voluntary Governance beyond the State

Even the most austere and radical forms of libertarianism—including those that advocate for the complete privatization of governance—acknowledge the necessity of institutional structures to prevent and respond to aggression. Liberty, in this view, is a fragile condition that must be actively protected. Without mechanisms for adjudication, restitution, and deterrence, liberty becomes vulnerable to petty criminality and organized coercion. Thus, even the most uncompromising libertarians accept that some form of law enforcement, rights protection, and dispute resolution is essential.

In his foundational work For a New Liberty: The Libertarian Manifesto, Murray Rothbard (1973) argues that just as markets can provide food and shelter, they can also provide courts, protection, and arbitration. The underlying assumption is that order and justice do not require centralized authority—only enforceable norms and decentralized competition.

In contrast, Barnett offers a more constitutionalist model of limited governance. While sympathetic to anarcho-capitalist theory, Barnett (1998, 2004) argues in The Structure of Liberty and Restoring the Lost Constitution that a minimal state may be justified so long as it operates within a strict legal framework that prevents the abuse of discretionary power. The state is legitimate only to the extent that it protects rights without becoming a source of aggression itself. As Barnett (1998, 10) puts it, “the only justifiable use of force is to repel force. Any institution claiming authority must be judged by whether its procedures are compatible with this principle.”

While both Rothbard and Barnett emphasize legal and institutional restraint, Edward Stringham takes the analysis a step further by showing that formal state power may not be required at all in many instances. In Private Governance: Creating Order in Economic and Social Life, Stringham (2015) presents a wealth of empirical and historical evidence demonstrating that private actors frequently create and enforce rules of conduct without relying on state intervention. His central claim is that the essential elements of law, norm generation, contract enforcement, and dispute resolution can and often do arise organically in market environments.

Stringham (2015, 15) introduces this insight succinctly: “Most enforcement of contracts and property rights is not performed by government, but rather by private parties who have a stake in maintaining a reputation for honesty and reliability.” To support this, he details the case of London’s coffeehouse-based stock exchanges in the seventeenth and eighteenth centuries—financial institutions that operated entirely without government regulation. Participants voluntarily adhered to community-enforced standards, understanding that fraud or breach of contract would result in reputational ruin and exclusion from future transactions. In this environment, the NAP was a practical norm, enforced not through force of law but mutual interest. This example illustrates a key libertarian insight: coercion is not the only, or even the most, effective means of achieving order. Stringham (2015, 23) explains: “Order is not the result of centralized design, but of decentralized processes guided by the logic of voluntary exchange.”

Moreover, Stringham challenges the common assumption that government is the default guarantor of social trust. He argues that repeated interactions, shared norms, and reputational mechanisms—“relational contracts”—can effectively align incentives without the need for centralized enforcement. As long as entry is voluntary and exit is viable, rule enforcement can function through consensus and competition rather than coercion.

Together, the work of Rothbard, Barnett, and Stringham underscores a broader point: liberty requires governance but not necessarily government. Whether through market-based courts, constitutional constraints, or decentralized enforcement regimes, the nonaggression principle finds its fullest expression in systems where force is tightly bound by consent and reciprocity. Additionally, it requires mutual interest, institutions, and shared norms. Where legal clarity, voluntary participation, and reputational incentives prevail, liberty is not only preserved but becomes self-reinforcing. As Stringham emphasizes, the lesson is not that such systems are flawless but that social order emerges naturally when coercion is minimized and incentives are aligned. Where institutions reflect the logic of nonaggression and voluntary cooperation, liberty emerges not as an exception to disorder but as its most functional antidote. Whether enforced by public courts or private norms, the principle is the same: freedom flourishes where coercion is constrained and where the architecture of governance rewards reciprocity over force.

While Rothbard champions privatized defense and Barnett emphasizes constitutional structure, Hayek shows that liberty depends on general, abstract norms—rules that emerge organically through social learning rather than political design. For him, freedom is not created by authority but discovered through evolving custom and secured by predictable, impartial law. For Hayek, coercion is sometimes necessary, but it is only legitimate when constrained by general and stable principles that individuals can foresee and integrate into their decisions. Hayek insists that liberty is sustained through predictability—that is, when people can plan their lives within a framework of rules that apply equally to all and do not shift with political whims. He draws a sharp distinction between what he calls “rules of just conduct”—those evolved norms grounded in custom and mutual restraint—and positive legislation, which seeks to impose specific political outcomes from above. Hayek believes that the rule of law is not merely a procedural formality but a necessary check on the concentration of power.

This vision places Hayek between the poles of Rothbardian privatism and statist control. He does not reject the need for legislatures, courts, or enforcement agencies, but he insists that they must operate within strict procedural constraints. Law must remain neutral, general, and impersonal, blind to power, status, or political objectives. Institutions should channel authority, not concentrate it. Their legitimacy depends on adhering to norms that evolve from public expectations rather than political ambition.

In Barnett’s view, the rule of law depends on three essential institutions: rules of conduct, adjudicative bodies, and enforcement mechanisms. Without these, legal norms become meaningless abstractions. “Without a framework for enforcing the rules of just conduct, liberty cannot be maintained; it will be overwhelmed by those who are willing to violate it” (Barnett 1998, 8).

This observation is doubly true at the international level. Without shared rules or enforcement mechanisms, the NAP cannot constrain aggression between states. In fact, it cannot even define what counts as aggression. Is a cyberattack an act of war? Is a trade embargo coercion? Is the sale of arms to separatists in a foreign country an initiation of force? In the absence of a shared legal framework, these questions cannot be resolved with reference to neutral standards. They are answered, if at all, through power politics and strategic advantage.

The 1931 invasion of Manchuria by imperial Japan continues to be paradigmatic. The 2014 Russian annexation of Crimea, despite the Budapest Memorandum, was met with minimal material consequence. The UN condemned the act, but no enforcement followed. International law, once again, proved to be a wish list. As Mearsheimer (2001, 52) writes, “when push comes to shove, international law has no independent means of enforcement, and great powers will ignore it when vital interests are at stake.”

This is not merely a practical defect—it is a structural one. The international system lacks a central authority to make nonaggression meaningful. Just like the League of Nations, it lacks universally binding procedures for arbitration, appeal, or restitution. States may submit to international courts voluntarily, but they may also exit those arrangements at will. There is no equivalent to domestic due process, no guarantee of compliance, and no shared understanding of what justice demands.

As a result of this environment, mutual recognition in and of itself cannot be assumed. This is not a marginal flaw but a core contradiction. The NAP assumes what international relations cannot deliver: a baseline of mutuality. Within domestic governance, libertarians expect that rights violations—whether theft, trespass, or fraud—can be meaningfully identified and remedied because all participants share a framework of legal definitions and procedural norms. That framework cannot be presumed across borders. The government of Switzerland may define aggression differently from that of China. Democratic states may see embargoes or sanctions as legitimate tools of pressure, while autocratic regimes may see them as acts of war. In short, there is no shared moral or legal grammar. As Randy Barnett (1998, 6) points out, “justice requires a framework in which the rights of persons are defined and secured. Absent such a framework, the very concept of justice becomes contested.”

This contested world goes on to be governed by suspicion, misinterpretation, and the relentless incentives of power. The state is then caught between the hammer and the anvil. When it acts on behalf of the citizen in this context, it cannot reliably know whether its actions will be met with economic sanctions, drone strikes, support and accolades, or nothing at all. One country may be invaded for harboring a terrorist cell, and another may be armed and subsidized for doing the same. To make matters even more confusing, both consequences might occur at the same time! The state has no recourse when confronted with the arbitrary will of a stronger adversary. In this environment, aggression is not punished but normalized; therefore, peace is the exceptional state.

This exact dilemma played out in the lead-up to World War I with the infamous “Willy-Nicky” telegrams. They are brimming with references to trust, restraint, and good faith, but they were ultimately powerless against the structural logic of alliance commitments, military mobilization, and the absence of any neutral adjudicator. Trust collapsed, and war followed. Libertarian ethics, for all their internal coherence, presuppose a high-trust environment in which persons or states agree on the nature of harm, the general scope of rights, and the legitimacy of enforcement. These conditions are present domestically but not globally.

This lack of predictability makes any attempt to transplant the NAP onto foreign affairs incongruent. Domestically, the state may be illegitimate, but at least it is legible. Even the attempt to create international legibility has been impossible. States are not even capable of creating a true contract. While treaties and accords may mimic domestic agreements, they lack the defining feature of enforceability. Promises are made when interests align and abandoned when they do not.

Institutions such as the United Nations and the World Trade Organization function only so long as the powerful permit them to. As Hedley Bull observes, rules in international society are obeyed when convenient, not because they are binding. To build foreign policy on the NAP is to mistake preference for principle and hope for structure. In a world without enforcement, even morality becomes optional. As such, the most damning feature of the international system becomes not its lawlessness but its reward structure. In this environment, states are not incentivized to abide by universal principles or honor voluntary agreements. They are incentivized to pursue power, maximize security, and preempt threats. In short, the global order does not reward virtue—it rewards leverage.

John Mearsheimer formalizes this logic in The Tragedy of Great Power Politics. For Mearsheimer, it is not just that states want power but that the structure of the system forces them to seek it. He writes, “The structure of the international system forces states which seek only to be secure nonetheless to act aggressively toward each other” (Mearsheimer 2001, 21). Thus the system behaves exactly as realists predict. It punishes not aggression but vulnerability. It does not elevate cooperation—it instrumentalizes it. Liberal institutions rely on the very structures of power they claim to transcend.

The belief in reciprocity assumes that norms can migrate—that a state can model peaceful behavior and its counterparts will eventually mirror it. The problem is that such moral suasion rarely works on actors who define morality differently, reject it altogether, or weigh it arbitrarily. Liberals assume that state behavior can be shaped by norms, institutions can tame aggression, and other actors share the same incentives for restraint. But the lesson of global politics is that intention does not beget imitation—deterrence does.

Restraint, in this context, becomes not a signal of virtue but a vacuum of power. Georgia’s limited military posture in 2008 did not dissuade Russia from invading South Ossetia and effectively redrawing the borders of a sovereign state. The 2014 collapse of the US-brokered status quo in Yemen, and the subsequent Saudi-led intervention, occurred despite years of multilateral dialogue and nonmilitarized diplomacy.

Friedrich Hayek warns against precisely this kind of system in which outcomes are detached from principle and performance is insulated from consequence. In The Road to Serfdom, he writes, “It is not reason which is the guide of life, but custom . . . evolved by a process of trial and error in which the errors are eliminated” (Hayek 1944, 23). It is almost as if Hayek is talking about the international system itself, which is incapable of eliminating its errors since aggression is not punished, and where no learning can take place since compliance is not rewarded. Institutions are always performative, norms are always a façade, and peaceful states are left to bear the costs of a fantasy. These are not just flaws in execution but a structural deficiency, which means that restraint will not teach peace and violation will not provoke reform.

The Wrong Unit of Analysis

For libertarians, rights belong to individuals. Governments possess no intrinsic moral status—they are, at best, tolerated as instruments to defend liberty and, at worst, seen as parasites or predators. Rothbard (1973, 84) made this point explicitly saying, “Only individuals have rights. There are no ‘group’ rights, whether of nations, races, classes, or states.”

And yet it is common to treat “aggression” between states as if they were moral agents entitled to noninterference. This is a category error: if a state has no rights, then the principle of nonaggression cannot meaningfully apply to it. The proper libertarian lens is not that one government should not aggress against another but that one government must not violate the rights of individuals.

This creates another problem: in the international system, states—not individuals—are the primary actors, and states often act not in defense of liberty but in pursuit of power, prestige, or regime survival. The decision-makers in authoritarian governments, for example, do not represent individual citizens in any libertarian sense. They act on behalf of coercive regimes, not voluntary associations. To respect the “sovereignty” of such regimes as if they were private property owners is to dignify coercion and misapply the NAP’s moral logic.

This problem becomes clearer when considering alliances, sanctions, or military interventions. Is a strike against a foreign dictator a violation of the NAP? Only if one grants that the dictator has a right not to be aggressed against—an absurdity under libertarian ethics. If, however, one frames the question in terms of individual rights, then the analysis shifts: the only relevant moral standard is whether the intervention protects or violates the rights of actual people, not whether it respects the geopolitical boundaries of violent institutions.

Liberal internationalists often fall into a similar trap. They speak of “the rights of nations” or the “sovereign equality” of states as if these were moral axioms. John Rawls (1999, 36), in The Law of Peoples, writes, “All societies, whatever their internal structures, must be treated as equals in international law.” To a libertarian, this is untenable. States are not equals in any moral sense—they are always coercive. It is fair to say that the state is little more than one of the five families and international relations is la Cosa Nostra. To treat them as equals under the law is to legitimize the illiberal—to morally flatten the distinction between regimes that respect rights and those that trample them and individuals. To defend liberty abroad, the libertarian must begin not with the state but the individual. And yet, the individual is rarely, if ever, empowered in foreign affairs. This is the tragic mismatch: the principle is sound, but the structure of the world does not accommodate it. Thus the NAP must be applied where it is philosophically coherent: among individuals rather than leviathans. The foreign policy wing of libertarianism must therefore shift from universal restraint to strategic judgment.

The Realist View of State Purpose: Realism and the Primacy of Survival

For realists, the state is a survival mechanism—a cold, calculating instrument for navigating a world where violence is always an option and security is never guaranteed. Nowhere is this view more clearly articulated than in the work of Hans Morgenthau (1948, 13), who asserted that “international politics, like all politics, is a struggle for power.” In his framework, the primary aim of the state is not liberty, equality, or progress—it is to persist.

Morgenthau (1948, 5) grounds his theory by saying that “politics is governed by objective laws that have their roots in human nature” and that chief among these laws is the principle of interest defined in terms of power. This is not a cynical view of the world—it is a descriptive one. Morgenthau does not celebrate the quest for power but rather explains it as the inevitable condition of state behavior in an anarchic international system. Morgenthau sees these institutions as a tool of the strong, observed when convenient and discarded when necessary.

This realist approach clashes directly with the view that diplomacy can be guided by shared norms or collective ethics. Figures like Woodrow Wilson, for instance, envisioned a global order founded on the spread of democracy and the rule of law. The League of Nations was premised on the idea that conflict could be curtailed through deliberation and common moral purpose. But Morgenthau warns against this “moral excess,” arguing that it leads to strategic blindness. He writes, “The light-hearted equation of a particular aspiration of a nation with the common good, and of the national interest with the interests of humanity, is morally wrong, politically dangerous, and intellectually shallow” (Morgenthau 1948, 10). Here, Morgenthau points out that conflating national goals with universal virtue is not only self-righteous but also strategically perilous, substituting desire for diagnosis and inviting overreach—and in this arena, survival is the precondition of all values. Morgenthau is not opposed to morality per se, but he insists that moral action in international relations must be filtered through the logic of necessity. As he argues, “there can be no political morality without prudence; that is, without consideration of the political consequences of seemingly moral action” (Morgenthau 1948, 12).

If consequences matter more than intentions, then international morality is defined not by its purity but by its effects. Sanctions, interventions, and treaties are not measured by whether they ought to work but whether they do. Morgenthau’s realism sees states as neither good nor evil. They are instead actors in a structurally antagonistic system, bound not by love of peace but by the fear of death.

From a libertarian perspective, this offers a bracing but necessary correction. While domestic libertarianism insists on moral clarity, nonaggression, voluntary interaction, and rights protection, foreign policy must navigate a world without courts, consent, or contracts. Morgenthau provides the intellectual foundation for this pivot. He does not propose abandoning morality but rather subordinating it to the primary moral imperative of international life: endurance.

Mearsheimer outlines five assumptions that define the international system: it is anarchic, hegemons possess offensive military capabilities, states can never be certain of others’ intentions, survival is the primary goal of every state, and states are rational actors. This leads to a single, inescapable conclusion: the best way to survive is to become the most powerful actor in the region. “The aim of every state,” Mearsheimer (2001, 21) writes, “is to be the hegemon in the system.” This understanding mirrors what Thucydides knew 2400 years ago: morality is irrelevant without the power to enforce it. In the Melian Dialogue, the Melians appeal to justice, divine favor, and the promise of Spartan aid. The Athenians respond bluntly: “The strong do what they can, and the weak suffer what they must.” The Athenians do not dispute the existence of justice or the morality of their actions; they simply deny that these are meaningful absent coercive power: “The standard of justice depends on the equality of power to enforce it” (Thuc. 5.89).

The fate of Melos embodies the logic of the anarchic system: only power restrains itself, if at all. As such, agreements, rights, and values have weight only when backed by credible force. Without enforcement, legitimacy is a sentiment, not a structure. The Melian Dialogue reminds us that justice without strength is irrelevant.

Realism’s View of Government as a Shield, Not a Moral Actor

Realism does not concern itself with how governments ought to behave but how they must behave to survive. Unlike liberalism—which often treats the state as a vehicle for promoting human rights, spreading democracy, or enforcing a moral world order—realism strips governance down to its elemental function: shielding the population from external coercion. In the realist view, the state is not a missionary but a barrier between citizens and chaos. It is not an arbiter of global justice but an instrument of national preservation.

This distinction is strategic. Morgenthau (1948, 17) argues that “the aspiration for power on the part of several nations . . . is not made under the impact of an abstract principle, but in response to the facts of life.” He rejects moralism in foreign affairs not because he denies the importance of values but because he understands that values must be subordinated to the imperatives of security. A rational state cannot afford to act on principle alone, because principles do not protect borders, deter adversaries, or guarantee strategic autonomy.

The liberal vision of the state often assumes that its legitimacy derives from its values and that its power is justified by the ideals it embodies. Realism, by contrast, reverses the sequence: a government must first survive before it can pretend to represent values. A destroyed state cannot defend liberty, and a subjugated people cannot practice democracy. As Morgenthau (1948, 10) warns, “a nation must put its survival first; for without survival, there can be no morality.” This claim is not a defense of amorality but an assertion that moral action is only possible within a framework secured by strength.

Realism is not nihilistic but diagnostic. It does not celebrate power; it recognizes its necessity. By treating the state as a shield rather than a teacher or redeemer, realism clarifies the role of government in a hostile world: to absorb danger, not project virtue. The moral function of the state, in this paradigm, is derivative of its ability to endure. Without sovereignty, there is no justice. Without security, there is no liberty. The state, in this formulation, is not celebrated, but it is necessary. It exists not to uplift, inspire, or engineer but to persist, deter, and defend. It is not a light unto the nations—it is a wall. And in the realist tradition, that wall, however morally uninspiring, is what makes freedom possible within.

Unified Libertarian Theory: A Libertarian Merger: Government as a Tool

Despite their divergent orientations—libertarianism rooted in moral philosophy versus realism grounded in strategic calculation—both schools of thought converge on a crucial insight: government is not a vehicle for virtue. It is a shield, a structure, a tool, and a coercive force, but it is not an end in itself, and it is certainly not a moral actor. This shared premise separates them both from the liberal tradition, which sees the state as a promoter of justice, equality, and the collective good. For libertarians and realists alike, the state’s legitimacy derives from what it prevents, not what it provides.

Libertarians have long insisted that the state is a necessary evil at best. Rothbard (1973, 46) declares that “the State is the organization of robbery systematized and writ large,” arguing that its coercive monopoly violates natural rights even when it acts under the guise of law. Government’s only legitimate function, in this view, is the neutral enforcement of contracts and the protection of individuals from aggression. It has no mandate to impose values, redistribute resources, or uplift society through paternalistic programs.

Realists, coming from a different intellectual tradition, arrive at a parallel conclusion: the state is not an agent of global justice or moral expression but a vessel of national interest. For both, the function of government is not to do good but to prevent harm. The difference lies in the scope: libertarians apply this logic to internal governance, while realists extend it to foreign policy.

In both frameworks, the state is functional, not aspirational. It does not create values; it safeguards space where free individuals or sovereign nations may pursue them. It’s a bouncer, not a preacher. Both groups understand that states must be judged by what they constrain, not by what they proclaim. They are united not in what they seek but in what they fear: the unchecked moralizing state, whether at home or abroad.

This structural agreement goes deeper: both philosophies tacitly accept that the government’s primary—and perhaps only—legitimate obligation is to those within its own borders. For libertarians, this is rooted in the social contract and the primacy of consent. The state derives its legitimacy from the individuals it governs, not from abstract moral duties to humanity at large. Its function is to protect the life, liberty, and property of its citizens, not to sacrifice them in pursuit of foreign ideals or global redistributive schemes. Any state action that jeopardizes domestic liberty in pursuit of international morality becomes illegitimate by definition.

Realists, while less concerned with philosophical and moral consistency, reach the same operational end point through a different logic. In the anarchic international system, the state survives only by securing its population’s strategic interests, economic stability, and physical security and by maintaining its national cohesion—not because of altruism or moral principles but out of necessity. A state that fails to serve its people risks internal collapse, regime change, or foreign subjugation. In this view, states must prioritize the interests of their own citizens over those of foreign populations, even when the latter are victims of aggression or suffering.

Both philosophies recognize the government as a construct, born not of moral perfection but necessity. The state is crafted to protect against disorder, invasion, and internal violence—but once empowered, it rarely remains passive. It develops interests of its own, rewards those who expand its reach, and resists constraints. What begins as a defensive instrument mutates into a dominant force—one that imposes where it once shielded and extracts where it once safeguarded.

The lesson is not to abandon the state altogether or deny the need that gave rise to it but to remember its nature. It is a being of brute force animated by human design—powerful but amoral. If left unchecked, it can destroy the very liberty it was created to preserve. That is why it must be constrained by real, durable, and structural limits—legal, institutional, and cultural. A government cannot be trusted to restrain itself; it must be built to be restrained.

This is the commonality: for libertarians, the state must be chained by consent and the NAP; for realists, it must be leashed by prudence and strategic necessity. So, ULT does not trust the state with moral judgment but instead treats it as a force that exists to secure survival rather than virtue. In this light, international restraint is rooted not in benevolence but focus. The state is an organ of domestic continuity. Its legitimacy arises from its population, and its function is to secure that population’s rights, territory, and autonomy—nothing more.

While both converge in their instrumental views of government, they seemingly diverge in the logic that underpins its legitimacy and scope. For libertarians, state power is justifiable only insofar as it emerges from the consent of the governed and is exercised narrowly to defend individual rights. For realists, by contrast, state legitimacy is judged not by ethical foundations but by efficacy and its capacity to preserve order, project strength, and ensure survival.

This is visible in their operative assumptions. The libertarian sees politics as a moral endeavor bounded by rights and voluntary association. The realist sees politics as an arena of necessity, where choices are made under conditions of uncertainty, scarcity, and danger. The libertarian asks, “Is this action just?” The realist asks, “Will this action succeed?”

Mearsheimer (2001, 12) captures this distinction in his argument that international politics is “a realm of survival where the state must do whatever is necessary to protect itself, regardless of moral considerations.” For the realist, there is no contradiction in a liberal democracy engaging in espionage, covert intervention, or war if these serve the national interest. For the libertarian, such actions could raise red flags because they are undertaken without individual consent and often involve the initiation of force, especially if there are no active hostilities. But the insistence on voluntary consent is misplaced: the primary actors are states, not individuals. Thus, the libertarian commitment to consent, while morally sound at the level of individual rights, is inapplicable. It is a fundamental error to apply the moral logic of personhood to political entities. A state is not a person and does not possess rights in any sense. It is not owed nonaggression but is bound only by the limits of its capacity and the constraints others can impose upon it. To assign rights to governments is to elevate abstractions above the people they govern—precisely the move libertarianism is designed to resist.

This matters profoundly when it comes to international relations. When one state coerces or undermines another, it does not automatically follow that rights have been violated. Only if individuals are targeted unjustly, outside the scope of defensive or retaliatory necessity, can the NAP be invoked. Libertarians, therefore, have no principled obligation to respect the sovereignty of states that systematically violate the rights of their own citizens or pose a threat. Nor should they object on moral grounds to strategic coercion directed at governments, institutions, or militaries, so long as such actions do not violate the rights of noncombatants. The real ethical crime is to allow aggressor regimes to operate unimpeded out of a misplaced fidelity to “state rights”—a concept utterly alien to libertarian thought.

In the interstate realm, libertarians must not merely permit but accept the necessity of strategic coercion when liberty is threatened. To do otherwise is to mistake the architecture of domination for a bearer of rights and to forsake the individuals that such structures oppress.

Critics of realism—especially libertarian critics—object to any endorsement of war on the grounds that it inevitably violates the NAP by harming noncombatants. This objection is weighty. War, by its nature, is worse than hell since everyone in hell deserves to be there. War is messy, destructive, and indifferent to fine moral distinctions. It is often impossible to conduct even the most restrained military campaign without some risk to innocent life. If the NAP forbids the initiation of force against individuals, how can libertarians ever condone a practice that entails so much collateral damage?

The answer lies not in moral absolution but moral triage. Libertarians must confront the uncomfortable truth that perfect adherence to the NAP in international conflict is not merely difficult—it can only be approached asymptotically. The battlefield does not provide the luxury of courtroom standards or clean separations between aggressor and innocent. While noncombatant immunity is a moral imperative in just war theory—and rightly so—its application in modern asymmetric warfare, cyber conflict, or prolonged state collapse is, at best, aspirational.

Hans-Hermann Hoppe (2001, 226) acknowledges this moral complexity when he writes, “One must not confuse the principle of non-aggression with pacifism. The former forbids initiating force. It does not require suicide in the face of an aggressor.” Hoppe’s point is crucial. The state has the obligation to defend its citizens against coercion. If an enemy regime poses a credible threat, the strategic use of force—including strikes against military infrastructure or command centers—may be justifiable, even if tragically imperfect in execution. This does not excuse indiscriminate violence, but it does demand the acknowledgment that the failure to act may result in greater loss of liberty than the constrained use of force.

Moreover, to reject all military action on the grounds that civilian harm is unavoidable is to commit an error of moral absolutism by elevating purity over protection and principle over people. Rothbard himself, despite his anarcho-capitalist leanings, accepted the legitimacy of self-defense, including violent resistance to tyrannical regimes. If domestic aggressors can be met with force despite the risk to bystanders, then foreign ones—especially those that endanger far more lives—can be as well.

This does not mean libertarians should adopt the utilitarian logic of total war. Quite the opposite: it demands an ethic of extreme restraint, tactical precision, and unflinching honesty about moral cost. It means supporting technologies, doctrines, and strategies that reduce civilian harm, not because states deserve mercy but because individuals do.

This leads to a final and critical tension: What, if any, moral obligations does a government have to foreign citizens? The libertarian instinct is rooted in universalism and natural rights theory and may suggest that aggression against any innocent person, regardless of borders, is equally unjust. But realism demands prioritization: not all claims can be honored simultaneously. States operate under scarcity—of time, resources, and knowledge. In such a world, obligations must be triaged.

Thus, ULT holds that the duty of a government is to secure liberty not for all humanity but for the individuals who authorize its existence—its citizens. A state’s legitimacy comes from its effectiveness as a defensive agent. It is a shield, not a missionary. As such, it owes its first and foremost obligations to those within its territorial and contractual jurisdiction.

This principle is well articulated by Robert Nozick in Anarchy, State, and Utopia, where he emphasizes that even a minimal state exists to protect its citizens from coercion—and that expansion beyond this role risks violating the very rights it was created to defend. Nozick (1974, ix) writes, “The state may not use its coercive apparatus for the purpose of getting some citizens to aid others.” If this applies to redistribution among domestic citizens, it applies even more stringently to obligations abroad. The resources used to protect foreign nationals, or to wage idealistic wars for their benefit, must come from someone—namely, the domestic taxpayer who can neither consent to nor benefit from such efforts.

This is not to say that foreign lives are worth less but that governments are not global humanitarian agencies. They are instruments of limited, purpose-driven defense. Just as one does not expect a neighborhood watch to police another neighborhood, one should not expect a national government to treat foreign nationals as equal claimants to its protective efforts.

A Merged Doctrine: From Division to Integration

ULT could be falsely described as a layered framework: liberty governs within, realism without. It may appear as if the state operates under two distinct philosophies rather than one ethic expressed through varying constraints.

In truth, there is no rupture between libertarianism and realism—there is only one objective: the preservation of liberty, pursued through different means depending on context. Internally, where institutions can enforce rights, the nonaggression principle is both morally compelling and administratively viable. Externally, in the absence of enforceable law, that same principle remains morally intact but strategically unenforceable.

Here, realism is not a departure from libertarianism—it is its expression under lawless conditions. It translates the ethic of nonaggression into tools the international order can recognize: deterrence, preemption, and bounded coercion. The state’s purpose remains constant; what changes is the mechanism of defense. Just as market actors adapt to scarcity without abandoning voluntary exchange, the state must adapt to anarchy without abandoning its obligation to liberty.

Strategic Continuity: Constraint across Domains

The merger of libertarianism and realism does not create a hybrid of clashing principles but a unified ethic of constraint expressed through different instruments. Whether through constitutions and courts at home or deterrence and calibrated force abroad, the same insight applies: power must be bound to be legitimate. Discipline is not merely a virtue—it is a survival mechanism.

Terms like “restraint” and “necessity” are not moral intrusions into realist strategy. But within ULT, these are not ethical afterthoughts—they are operational imperatives. Overreach abroad is as corrosive as tyranny at home. What law accomplishes domestically through due process, realism must achieve internationally through limited objectives, rules of engagement, and proportionality. Just because force may be used doesn’t mean it should be. War is chaotic and unpredictable, and it can easily become a threat to the liberty of the initiating state. These constraints are not borrowed from humanitarianism but drawn from the failures of empires and the logic of self-preservation. They do not dilute liberty—they enforce it.

ULT rests on a single ethic shaped by circumstance. Liberty remains the constant; what changes is the medium through which it is defended. Where law governs, liberty is protected by institutions. Where law fails, liberty must be safeguarded by strategy. Realism, seen through a libertarian lens, is not a philosophical rival but the doctrine’s external posture—how a free order survives in an anarchic world. The state needs to be morally identical in all domains, and it must be principled and consistent in refusing to let power go unchecked. Thus emerges a unified architecture: law where possible, force where necessary, always constrained, and guided by the preservation of liberty. For liberty to endure, it must be shielded by strength—but that strength, if unbounded, becomes the very danger it was summoned to resist.

Operational Doctrine: Force as a Calculated Instrument

Having established that libertarianism and realism are not opposing philosophies but a unified ethic applied in different conditions, the remaining question is one of application: How should a state act when it must operate without law? ULT answers not merely with ideals but with constraints. It affirms that liberty is preserved not only by institutions but also by the strategic judgment of those entrusted with force.

Force, in this doctrine, is not forbidden, but it is always weighty. The legitimate use of power abroad is bound by three interlocking criteria: interest, necessity, and proportionality. Interest provides the justification, necessity the urgency, and proportionality the limit. The state must not act because it can but only because it must. This is not pacifism—it is discipline by design. It reflects the recognition that every exercise of force generates friction: enemies, expectations, and obligations. As Machiavelli (1996, 219) warns in the Discourses on Livy, “no enterprise is more likely to bring about the ruin of a prince than the undertaking of a war without justification or necessity.”

This is so much more than simple historical wisdom—it is a foundational and structural principle. Force used in excess corrodes liberty because of the waste and blowback; force used reflexively threatens to reverse engineer authoritarian logic at home. Preventing this drift requires institutional doctrine, not personal virtue. The sword exists, but it must remain sheathed until prudence—not passion—draws it.

Even when force is justified, its expression must be bounded. The objective must be clear, the duration limited, and the costs understood as best as possible. War must not be an instrument of transformation but a shield for sovereignty. ULT rejects all ideological crusades, because the means of pursuing them are corrosive to the polity’s own freedom since they easily breed hatred. To protect liberty at home, the state must refuse the temptation to moralize violence abroad.

Machiavelli (1998, 61) offers further clarity. In The Prince, he writes, “It is much safer to be feared than loved . . . but one ought to avoid making oneself hated.” This is the logic of calibrated deterrence. The state must project the capacity for force without indulging in its excess. Power must be legible, not theatrical—credible, not performative. Fear, when measured, deters. But hatred, once earned, destabilizes.

In sum, the operational doctrine of unified libertarianism treats force not as an extension of virtue but as a tool of last resort. Its function is singular: to deter aggression, defend sovereignty, and prevent coercion from displacing the voluntary order at home. It is wielded not to purify the world but to protect the conditions under which liberty can exist at all.

While this may seem to lead to a nihilistic worldview, ULT does not endorse moral nihilism. While it accepts that realist logic must shape foreign policy, this doesn’t imply that all actions pursued in the name of state interest are justified. Strategic realism, as understood within this framework, is a doctrine of survival, not a warrant for cruelty. It acknowledges that force may be necessary to deter aggression or defend sovereignty, but it draws a clear line between legitimate defense and unrestrained violence. Deliberately targeting civilians, acts of genocide, and ethnic cleansing are not strategic necessities—they are violations of order, liberty, and any stable political ethic.

Even realists caution against the misuse of power. Morgenthau (1948, 10) argues that foreign policy must be guided by prudence and moral restraint rather than ideological zeal or cruelty: “Realism . . . does not require, nor does it condone, disregard of moral principles. But it requires a sharp distinction between the moral aspirations of a nation and the universal moral laws.”

This distinction reinforces the idea that while states may act in their interest, those actions must remain within the bounds of proportionality and necessity. Realism, rightly understood, demands discipline, not license. This distinction is essential. A state may use force to secure its borders, preempt existential threats, and respond to violations of its sovereignty, but such power must not be exercised indiscriminately. The libertarian rejection of collective guilt domestically must extend internationally. War may pit governments against one another, but it does not dissolve the moral status of individuals. Civilian life remains inviolable. The legitimacy of a free society cannot be preserved through methods that disregard the very principles it claims to defend.

The doctrine articulated in ULT is a framework for disciplined statecraft, not a moral loophole. While the NAP cannot govern international relations in its original legalistic form, the moral insight behind it endures: coercion without due cause is illegitimate. Realism, as incorporated into this theory, remains a strategic ethic, not a pretext for domination. Force is justified only when it protects the liberty of those the state is duty bound to represent, not when it drifts into the politics of annihilation.

The Unified Libertarian Theory of Government: The Logic of Institutional Behavior

ULT draws from public choice economics, realism, and libertarianism to understand how governments behave. Just as individuals act in pursuit of self-interest, so too do institutions. Politicians seek reelection, bureaucracies seek expanded budgets, and states act to preserve their own structure and influence. As James Buchanan and Gordon Tullock (1962, 13) argue in The Calculus of Consent, political actors respond not to idealized notions of public good but to the incentives and constraints of their institutional roles.

This logic applies directly to foreign policy. Governments do not intervene abroad solely to protect liberty or preserve justice. They often act to maintain strategic relevance, justify military budgets, or placate domestic constituencies. Robert Higgs (1987, 68), in Crisis and Leviathan, demonstrates how state power expands most aggressively during crises, many of which are framed as foreign threats. These interventions may be clothed in moral language, but their underlying driver is institutional survival.

The state, in this sense, is less like a moral actor and more like a firm. It serves a defined constituency—its citizens—and its legitimacy depends on performance, not virtue. When it fails to protect liberty, it fails in its function. And like a firm, it may advertise social values, but its continued existence depends on its ability to deliver value to shareholders. Similarly, even a state viewed skeptically, as coercive or parasitic, can retain legitimacy only as long as it performs its protective role effectively. Like corporations exiting failed ventures to preserve shareholder value, states should abandon foreign policies that no longer serve domestic liberty. Just as a firm that clings to sunk costs damages its future viability, a government that continues interventions out of pride or inertia undermines its legitimacy. In both domains, survival depends on responsiveness to core stakeholders, not fidelity to abstract objectives. In the absence of performance, both lose their mandate. ULT insists that we judge states not by their stated intentions but by whether they uphold the liberty of those they are meant to serve.

Moral Passivity as Complicity

ULT challenges the notion that inaction is inherently moral. While libertarian thought often prizes nonintervention almost universally, ULT distinguishes between principled nonintervention and ethically consequential silence. When aggression is already underway, a state’s refusal to act is permissive rather than neutral. A government that declines to resist predation allows the coercive order to shift in favor of the aggressor so that moral passivity becomes a form of complicity.

Hannah Arendt’s (1963, 21) insight into the “banality of evil” helps frame this dilemma. In Eichmann in Jerusalem, she describes how atrocity can emerge not from hatred but from bureaucratic inertia and institutional detachment . Arendt’s point is that evil often thrives when individuals and institutions refuse to think beyond their formal roles. This logic applies to international politics as well. States that abstain from action under the guise of neutrality may end up enabling violence through omission.

History offers sobering examples. In 1994, over eight hundred thousand Rwandans were murdered in one hundred days while the international community debated legal definitions of genocide (2002, 329). In 1995, Dutch UN peacekeepers failed to prevent the massacre of over eight thousand Bosniak men and boys in Srebrenica. These were not failures of information or capacity—they were failures of will. In both cases, the absence of intervention went beyond strategic choice and became a contributing factor to catastrophe. The cost was not only humanitarian but also shifted the strategic balance, undermining future deterrence.

ULT accepts that the state cannot be everywhere at once. But it also affirms that liberty cannot survive in a world where the only actors willing to use force are those least constrained by ethics. A state grounded in ULT’s principles must remain vigilant. It must recognize that there are moments when inaction surrenders rather than preserves peace. Force should never be used to moralize, but sometimes it must be used to defend the only space the state is built to protect.

Moral Limits without Moralism

ULT rejects both moral imperialism and reflexive pacifism. It does not view war as a tool to spread ideology, nor does it idealize inaction as a higher form of virtue. Instead, it accepts the moral complexity of international affairs and grounds its use of force in a limited, defensive ethic. A free state may be forced to act—not to transform the world but to shield the liberty that exists within its own borders, all while acknowledging that war is a chaotic, messy affair. As such, war should only be entered with the greatest of caution, since it is almost impossible to calculate how the outcomes will help or hurt the liberty of the polis.

This is why ULT is sharply critical of the moral ambition that has often accompanied modern interventionist policy. The neoconservative and neoliberal project of exporting democracy through armed force failed not only strategically but conceptually. As Claes Ryn (2003, 47) argues in America the Virtuous, a foreign policy driven by abstract ideals tends to disregard culture, sovereignty, and prudence . The result is not liberty abroad but instability and resentment. Iraq, Afghanistan, and Libya are case studies in the dangers of moral overreach.

At the same time, ULT resists the notion that all foreign engagement is unjust. Some libertarians argue that any projection of state power beyond national borders violates the NAP, but this view ignores the reality of external threats. When coercion is initiated by others, the refusal to respond constitutes an abandonment of liberty. A doctrine that forbids resistance is not principled—it is paralyzed.

Force, under ULT, is never ideal. It is a regrettable necessity, bounded by proportionality, guided by interest, and judged solely by whether it defends liberty at home. Unlike moral crusaders, ULT does not seek to save others. Unlike staunch noninterventionists, it does not pretend the world will leave a free society untouched. It acknowledges that the liberty of the nation has enemies and that freedom, once secured, still requires protection.

The legitimacy of state action abroad must rest on clear limits, defined objectives, measurable outcomes, and disciplined exit strategies. ULT does not offer moral comfort—it offers moral clarity. The state must not act to glorify itself or its values. Instead, it must act, when it must, to keep open the space in which free individuals can live without fear.

The Sword and the Hand That Wields It

This is the central premise of ULT: the state must be judged differently in its internal and external functions, not because its nature changes but because its obligations do. It is one entity operating in two environments under a single imperative, which is to preserve liberty where law can govern and defend it where its monopoly cannot reach. The sword of the state may strike outward in defense, but it must never turn inward against the hand that wields it. Coercion abroad, when necessary and bounded, can be justified; coercion at home, when aimed at the citizenry, cannot. That distinction marks the line between governance and abuse and between legitimacy and failure.

This conclusion returns to the core principles articulated throughout this doctrine and its progenitor parts. The state’s legitimacy is rooted in fiduciary duty, not moral posturing. Internally, it enforces liberty through institutions; externally, it preserves liberty through calibrated deterrence. In both realms, constraint is not weakness but design. Constraint is not a concession—it is the architecture that holds liberty in place. Whether enforced through courts or calibrated through strategy, limits are the design language of a free polity.

The state’s authority, like a contract, is revocable. Its moral status is not intrinsic but conditional on continued service. A free citizenry must remain alert to this arrangement, willing to reclaim power when the state oversteps or forgets its role. Just as a corporation’s charter can be revoked by shareholders when it fails to serve their interests, a state’s legitimacy can be rescinded by the people it is supposed to protect.

ULT accepts the irreducible fact of a dangerous world and the imperfect instruments with which we must navigate it. It does not moralize power, but it does refuse to abandon principle. A state faithful to this doctrine will neither evangelize nor withdraw. It will act, when necessary, to defend the liberty that justifies its existence. The state’s power is not its own but is borrowed from those it serves. If it forgets that, then instead of evolving into something new, it reverts into the very instrument of coercion it was meant to contain.

Conclusion

Libertarianism begins with the foundational belief that liberty is the natural condition of every individual and that the state, if it must exist at all, must be bound by unyielding ethical and institutional constraints. This foundation remains inviolable within a society governed by law, reciprocity, and enforceable norms. But beyond the domestic sphere, where such institutions dissolve into power politics and strategic opacity, the same moral code falters. The nonaggression principle, coherent and defensible within borders, collapses into naivete when applied to a system of states that do not share its grammar, let alone its ethics. In this domain, power precedes principle and survival often determines legitimacy.

Unified libertarian theory does not toggle between liberty and power but recognizes that both emerge from the same condition: life without guarantees. Whether confronting the anarchy of the international system or the complexity of domestic pluralism, the essential logic remains the same: power must be bound, not eliminated, and liberty must be structured, not presumed.

ULT asserts that realism and libertarianism are not rivals but reflections, each responding to the same problem of survival under uncertainty but at different scales and under different institutional constraints. In this view, the NAP and the logic of deterrence are parallel expressions of strategic restraint. One operates through law and the other through prudence, but both aim to prevent coercion and preserve autonomy.

Liberty is neither defended by moral sermons nor preserved by dominance alone. It endures when institutions, legal or strategic, discipline force without collapsing into submission or conquest. Unified libertarian theory is the nonaggression principle applied to its fullest in the international system—while being the best way forward for those with strong moral convictions in a fallen world.