Realism vs Liberalism: Mearsheimer on War & Peace | Lex Fridman Podcast

Democratic peace theory argues liberal states don't fight each other due to constitutional checks, electoral caution, and collective security arrangements. Neoliberal institutionalism accepts anarchy but emphasizes international institutions that provide information, punish defectors, and influence state behavior. While institutions cannot eliminate anarchy, they change the international environment by shaping preferences and creating hesitation to abandon arrangements.

Neoliberalism includes several specific theories: Democratic Peace Theory argues democratic states are less likely to war with each other; Multilateralism advocates resolving disputes through international institutions; Republican Liberalism emphasizes democratic values; Economic Interdependence argues free trade and investment create incentives for peace. The theory holds that when states share democratic values and are economically connected, they are more likely to cooperate and less likely to conflict.

Liberalism, precursor to liberal IR theory, holds that state preferences (culture, economy, government type) determine behavior, unlike realism's unitary actor model. Interaction extends beyond politics to economics and culture, enabling cooperation and absolute gains. The democratic peace theory claims liberal democracies never wage war against each other—a disputed empirical claim. Neoliberal institutionalism advances liberalism by arguing international institutions enable successful state cooperation despite anarchic structures. Post-liberal theory reinterprets sovereignty and autonomy as duties rather than rights, with international organizations holding states accountable, making sovereignty a variable capacity of good governance rather than absolute right.

Neoliberalism holds that democratic states are more likely to cooperate with one another and less likely to engage in conflict. This 'democratic peace' thesis suggests that democratic governments, which are accountable to their citizens and constrained by institutions, have incentives to pursue peaceful international relations. Neoliberals argue that the spread of democracy and the establishment of democratic institutions worldwide will promote international peace and cooperation.

Neoliberal internationalism, associated with scholars like Francis Fukuyama, builds on democratic peace theory, which argues that liberal democracies do not fight each other. This perspective suggests that promoting democracy globally will lead to lasting peace. Neoliberal internationalism proposes establishing peaceful unions among liberal states where war becomes impossible. However, critics challenge this view by noting that powerful states dominate international institutions like the UN, IMF, and World Bank, shaping agendas to serve their interests rather than facilitating genuine cooperation among equals. This critique highlights the gap between theoretical ideals and institutional realities in international relations.

This lecture explores two major paradigms in international relations theory: Marxism and Constructivism. Marxism, emerging in the 20th century, posits that economic interests and class struggle are the primary drivers of international relations, with the economic base determining all other aspects of state behavior. World-Systems Theory, a neo-Marxist approach, divides the world into core, semi-periphery, and periphery states, explaining global inequality through unequal exchange and exploitation. Constructivism, the youngest paradigm (emerging in the 1970s-80s), argues that international relations are social constructs shaped by identities, emotions, and subjective perceptions rather than purely material interests. Unlike realism and liberalism, which focus on rational calculations, constructivism emphasizes that states are living organisms with fears, cultural contexts, and collective responsibilities, making conflicts unpredictable and requiring ethical evaluation.

Constructivism in international relations theory focuses on how ideas, identities, and social structures shape state behavior, arguing that shared knowledge, norms, and identities are fundamental to understanding international politics. Marxism emphasizes that economic structures and class relations drive international relations, viewing capitalism as a system requiring transformation. These theories complement realism and liberalism by highlighting the role of social processes and economic factors in shaping global politics, offering comprehensive frameworks for analyzing international affairs.

Constructivism is a theoretical perspective in International Relations that emerged after World War II as an alternative to traditional theories like Realism and Liberalism. While traditional theories focus primarily on material factors such as power, national interest, and international institutions, constructivism argues that non-material factors—including history, norms, cultural values, identity, and social interactions—equally shape state behavior. The core insight is that reality in international relations is socially constructed rather than objectively fixed, meaning that shared understandings, beliefs, and social processes play a fundamental role in determining how states interact and behave.

Constructivism challenges rationalist dominance by emphasizing how ideas, collective values, and social identities shape international politics. Unlike realism (security/material power) or liberalism (economic interdependence), constructivism focuses on ideational factors that can trump material concerns. Perception matters: US military expansion concerns Cuba more than Canada. Marxism and critical security studies reject realist-liberal views, focusing on economic/material aspects through historical materialism. Marxists view the international system as integrated capitalist pursuit of capital accumulation. World system theory (Wallerstein/Lenin) argues global capitalism creates core-periphery exploitation. Antonio Gramsci's hegemony concept analyzes capitalism's ideological hold.

The late 20th century saw the rise of constructivist approaches challenging realist paradigms. Alexander Wendt's work on the agent-structure problem questioned whether individual agents or structural forces primarily determine international outcomes. Hedley Bull's 'The Anarchical Society' (1977) provided a comprehensive analysis of the international system as an anarchical society, distinguishing it from John Bull's 'World Society' concept. Susan Strange's 'Casino Capitalism' (1989) examined financial globalization and its implications for state sovereignty. Benedict Anderson's 'Imagined Communities' (1983) explored how nations construct collective identity, while Nicholas Onuf's 'World of Our Making' (1989) contributed constructivist critiques of realism. These works represented a fundamental shift toward understanding how ideas, identities, and social constructs shape international relations.

International relations theory has been dominated by two competing schools: the liberal approach and the realist approach. The liberal approach, dominant in the 1990s, posits that democratic nations do not fight each other and that economic interdependence prevents conflict. The realist approach, gaining prominence again, assumes nations will pursue their interests regardless of ideological considerations and that the international system is inherently anarchic without a central authority. The Ukraine conflict has demonstrated the failure of liberal assumptions, with the war showing that nations will fight regardless of economic ties or democratic governance.

The liberal expectation that China would become a democratic liberal state through economic integration failed. As China became more powerful, it began to want to dominate East Asia like the United States. The NATO expansion to the Russian border was a strategic error that created an existential threat Russia perceived as such. The expansion was unnecessary because Russia is the weakest of the three great powers and does not represent a threat of European domination. The war in Ukraine is strategically damaging to the United States because it ties down American resources in Europe and pushes Russia into China's arms. It is very easy for states to enter wars but extremely difficult to exit them, especially for great powers concerned with reputation. The realist logic has returned as the world moved away from unipolarity, with three great powers now competing for survival in an anarchic system.

Realist foreign policy theory proves inadequate for understanding the Russia-Ukraine war because it reduces international relations to a simple clash of state interests like billiard balls, ignoring internal state factors entirely. This theoretical blind spot prevents realists from recognizing the critical role of Russian ideology, political culture, and leadership under Putin. The failure to acknowledge values, norms, democracy, and liberalism as driving forces means realists cannot explain why Ukraine resists so effectively or why Moscow's strategy has been so flawed.

This segment introduces realism in international relations, explaining how John Mearsheimer's theory predicts state behavior based on power dynamics and security concerns. Glen Dizena applies this framework to the Ukraine-Russia conflict, arguing that NATO's eastward expansion after the Cold War violated implicit agreements made during German reunification, triggering Russia's defensive response. The analysis traces the historical chain of events: the 1990 gentlemen's agreement assuring Gorbachev NATO wouldn't expand eastward, followed by Western expansion into former Warsaw Pact countries. Russia established a 'red line' policy rejecting NATO membership for Ukraine and Georgia. The 2014 Euromaidan revolution and Russian annexation of Crimea marked the first major confrontation. President Zelenskyy's 2022 Munich speech explicitly stating Ukraine's intent to join NATO served as the immediate catalyst for Russia's full-scale invasion, demonstrating how accumulated grievances and broken assurances can escalate into armed conflict.

The realist school explains state behavior through rational actors maximizing power and security in an anarchic international system without higher authorities. States compete for power because they cannot determine others' intentions. Applied to Russia's invasion of Ukraine, realism argues Putin acted to prevent NATO expansion threatening Russia's survival, not for imperial conquest. This differs from Western narratives portraying him as an imperialist. The framework emphasizes balance of power over ideology, suggesting states prioritize survival through power accumulation rather than ideological goals.