In 1795, the German philosopher Immanuel Kant published a slim treatise called Perpetual Peace in which he proposed three conditions for ending war among nations: every state should be a republic (a representative government accountable to its people), republics should form a federation governed by international law, and the rights of individuals should be respected regardless of nationality. Two centuries later, these three conditions—democracy, international institutions, and human rights—form the intellectual pillars of liberal internationalism, the theoretical framework that built the postwar international order and continues to shape, however imperfectly, how the Western world thinks about global governance.
The institutions that liberal internationalism created are everywhere: the United Nations, the International Monetary Fund and World Bank, the World Trade Organization, NATO, the European Union, the International Criminal Court, and hundreds of multilateral agreements governing everything from postal service to nuclear weapons. These institutions rest on a set of propositions that realists consider naive and that the post-2016 era of populism, Great Power Competition, and democratic backsliding has severely tested: that democracies rarely fight each other, that trade creates mutual dependence that raises the costs of war, that institutions provide frameworks for cooperation that self-interested states could not achieve alone, and that the international order should be governed by rules rather than raw power.
Intellectual Origins¶
Kant and the Enlightenment¶
Kant’s Perpetual Peace is the founding text of liberal internationalism, though its proposals seemed utopian in an era when absolute monarchs waged war with casual regularity. Kant’s innovation was to argue that peace was not merely desirable but achievable—if states adopted the right institutions:
Republican government: Kant argued that republics (democratic states) would be less prone to war than autocracies because the citizens who bear the costs of war (through taxes, conscription, and destruction) would have a voice in deciding whether to fight. Autocrats could wage war at personal whim; democratic leaders answered to populations that preferred peace.
A federation of free states: Rather than a world government (which Kant feared would become despotic), states should voluntarily form a federation governed by shared rules. International law, not the Balance of Power, would regulate their relations.
Cosmopolitan right: Individuals should enjoy certain rights regardless of nationality—the right to hospitality, to travel, to be treated as fellow humans rather than enemies. This principle anticipated the modern human rights regime.
Woodrow Wilson and the League¶
Kant’s ideas remained largely academic until World War I shattered the European balance of power system and discredited the realist approach to international order. President Woodrow Wilson seized the moment to propose a new architecture based on liberal principles:
National self-determination: Peoples had the right to govern themselves, dissolving the empires that had dragged the world into war.
Collective security: Rather than relying on balance of power (which had failed catastrophically in 1914), states would guarantee each other’s security collectively. An attack on one would be treated as an attack on all.
The League of Nations: An international organization would provide the institutional framework for collective security, peaceful dispute resolution, and international cooperation.
Wilson’s vision was noble but flawed in execution. The United States Senate refused to ratify the League of Nations treaty, leaving the institution without its most powerful potential member. The League could neither prevent Japanese aggression in Manchuria (1931), Italian aggression in Ethiopia (1935), nor German aggression in Europe (1938-1939). The failure of the League—and the catastrophe of World War II—did not discredit liberal internationalism; instead, it taught that liberal institutions required enforcement mechanisms and American engagement to function.
The Postwar Order¶
Bretton Woods and the Economic Architecture¶
In July 1944, while the war still raged, 730 delegates from 44 nations gathered at a resort hotel in Bretton Woods, New Hampshire, to design the postwar economic order. The result was a system that reflected liberal internationalist principles:
The International Monetary Fund would stabilize exchange rates and provide short-term financing to countries facing balance of payments crises—preventing the competitive currency devaluations that had deepened the Great Depression.
The World Bank (initially the International Bank for Reconstruction and Development) would finance postwar reconstruction and, later, development in poorer countries.
The dollar-gold standard pegged major currencies to the US dollar, which was convertible to gold at $35 per ounce. This provided the monetary stability that had been absent during the interwar period.
The General Agreement on Tariffs and Trade (GATT, 1947) promoted trade liberalization through successive rounds of tariff reductions—reversing the protectionist spiral of the 1930s that had strangled world trade and contributed to the political extremism that produced war.
These institutions embodied the liberal conviction that economic interdependence promotes peace: countries that trade with each other have shared interests in stability and higher costs from conflict.
The Democratic Peace¶
The most influential empirical claim in liberal theory is the democratic peace: the observation that established democracies rarely, if ever, wage war against each other. The statistical pattern is striking—despite hundreds of interstate wars since 1816, wars between established democracies are virtually nonexistent. This finding has been called “the closest thing we have to an empirical law in international relations.”
Several mechanisms have been proposed to explain the democratic peace:
- Institutional constraints: Democratic leaders must build public support, secure legislative approval, and face electoral accountability for military decisions—constraints that slow the march to war and create opportunities for diplomatic resolution
- Normative explanations: Democracies share norms of compromise, negotiation, and non-violent conflict resolution that they extend to their relations with other democracies
- Informational transparency: Democratic political processes provide more information about leaders’ intentions, reducing the uncertainty that fuels the Security Dilemma
Critics question whether the democratic peace is truly a product of democracy or an artifact of other factors—American hegemony, Cold War alliance structures, or economic interdependence among wealthy states. Realists argue that the pattern will not survive the return of Great Power Competition, when structural pressures override democratic norms.
Critiques¶
The Realist Challenge¶
Realists have always been liberal internationalism’s sharpest critics. Their objections are fundamental:
Institutions are epiphenomenal: International institutions reflect the distribution of power, not an independent force that shapes state behavior. The UN works when great powers agree; it fails when they don’t. NATO functions because the United States underwrites it; without American power, NATO would be a debating society. Institutions are tools of the powerful, not constraints on them.
Anarchy persists: No amount of institutional engineering can eliminate the fundamental condition of anarchy—the absence of a central authority guaranteeing states’ survival. States must ultimately rely on themselves, and when survival is at stake, they will violate institutional norms without hesitation. Russia violated international law by invading Ukraine; the United States violated it by invading Iraq. In neither case did institutions prevent the action.
The democratic peace may be fragile: The absence of war among democracies during a period of American hegemony may not indicate a permanent pattern. If American power declines and democratic states face genuine security threats, the norms that supposedly prevent inter-democratic war may prove less durable than liberals assume.
The Global South Critique¶
From the perspective of developing countries, liberal internationalism has been less a framework for cooperation than a mechanism for Western dominance:
Unequal institutions: The IMF, World Bank, and WTO were designed by and for wealthy Western states. Voting power in the IMF is weighted by economic contribution, giving the United States effective veto power. “Structural adjustment” programs imposed by the IMF in the 1980s and 1990s—requiring privatization, austerity, and market liberalization—devastated developing economies while serving creditor interests.
Selective application: Liberal principles have been applied selectively. The United States promoted democracy in some countries while supporting dictators in others—Pinochet in Chile, the Shah in Iran, Suharto in Indonesia—when strategic interests required it. The “rules-based order” often meant rules that benefited the powerful and were enforced against the weak.
Economic exploitation: Globalization—the free movement of capital, goods, and services that liberal internationalism promotes—has produced aggregate wealth gains but also devastating inequality, deindustrialization in the Global North, and continued dependency in the Global South.
The Populist Backlash¶
Since 2016, liberal internationalism has faced its most serious political challenge. Brexit, Trump’s “America First” policy, the rise of nationalist movements across Europe, and democratic backsliding in Hungary, Poland, and elsewhere reflect a widespread rejection of liberal internationalist premises:
- Sovereignty over cooperation: Populist movements assert national sovereignty against international institutions and agreements
- Protection over free trade: Workers who lost jobs to globalization reject the claim that free trade benefits everyone
- Identity over cosmopolitanism: Nationalist movements emphasize cultural, ethnic, or religious identity against liberal internationalism’s universalist aspirations
Contemporary Relevance¶
Liberal internationalism is under siege but not dead. The institutions it created continue to function, however imperfectly. The EU survived Brexit. NATO expanded in response to Russia’s invasion of Ukraine. The WTO, despite paralysis, still regulates most global trade. The democratic peace, whatever its theoretical foundations, continues to hold empirically.
The question is whether these institutions can adapt to a world that looks increasingly different from the one they were designed for. China’s rise challenges the assumption that economic integration produces political liberalization. Russia’s aggression challenges the assumption that international law constrains great powers. Climate change requires unprecedented cooperation among states with deeply conflicting interests. And the democratic backsliding within Western countries themselves undermines the moral authority on which liberal internationalism ultimately depends.
Sources & Further Reading¶
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The Great Delusion: Liberal Dreams and International Realities by John J. Mearsheimer — The most powerful realist critique of liberal internationalism, arguing that the attempt to spread democracy and build a rules-based order was doomed to fail and has produced unnecessary wars.
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After Victory: Institutions, Strategic Restraint, and the Rebuilding of Order After Major Wars by G. John Ikenberry — The leading liberal theorist’s argument that the US-led institutional order has been remarkably durable because it binds American power within multilateral frameworks.
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Perpetual Peace and Other Essays by Immanuel Kant — The foundational text of liberal internationalist thought, proposing conditions for lasting peace among nations that remain influential two centuries later.
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Power and Interdependence by Robert O. Keohane and Joseph S. Nye Jr. — The classic statement of how economic interdependence and international institutions modify the realist picture of international politics.