Chapter 3

The causes of World War II may seem simple at first glace – the war was started by Adolf Hitler, a single racist dictator who led his country into a war of expansion. But explaining World War II becomes more complicated when we ask how Hitler came to power in the first place and whether war would have started if he had not been in power. Explanations from the domestic and systemic levels of analysis point to deeper issues in international politics as leading to another major conflict.

The liberal perspective emphasizes changes in the role of the League of Nations, which had been created in 1919 to fix the problems – namely the balance of power – that had led to World War I. The League of Nations replaced the decentralized balance of power with collective security; under this arrangement, a preponderance of power would be used against aggressors, while economic sanctions and disarmament would decrease the role of force in international relations. In the lead-up to World War II, the League of Nations failed because it lacked the support of the great powers, because it couldn’t offer effective security guarantees (while disarmament increased insecurity), and because the principle of unanimity meant that aggressive states could veto actions against themselves. In the end, the institutional weaknesses of the League of Nations couldn’t check the aggression of states like Japan and Italy.

The realist perspective argues that, like before World War I, the problem was a united and strong Germany. The Treaty of Versailles was intended to weaken Germany, but Germany managed to gain power once again and, as a result, disrupted the balance of power and increased the security dilemma. In the 1920s, Germany managed to escape diplomatic isolation through the Treaty of Rapallo and the Treaty of Locarno. Then, in the 1930s, Hitler and the Nazi government increased Germany’s military power and began expanding its territory. The rise of Germany raises two questions for the realist perspective. First, why did no one balance against Germany? As Germany gained power, the other great powers did little to stop it – instead of balancing; they pursued policies of appeasement, buckpassing, and bandwagoning. Second, why did Germany overexpand? Possible realist explanations for overexpansion are that anarchy encouraged conquest, that Germany’s cartelized domestic politics encouraged expansionism, which a tripolar distribution of power (among the United States, Germany, and the Soviet Union) was extremely unstable, and that Germany feared the Soviet Union would become stronger in the future.

The identity perspective focuses on changes in the ideas that formed the basis for European politics. The “old Europe” – ended by World War I – was founded upon substantive religious beliefs and the equal rights of sovereign monarchs. The “new Europe” was organized around norms of nationalism and self-determination, and included a prominent role for international institutions. Nationalism – for both great powers and small powers – created divisions among states, even as it began to manifest in competitive forms that included elements of irredentism, fascism, anti-Semitism, xenophobia, and racism. As ideas became more divergent and more competitive, the new and old states of Europe drew closer to war.

Learning Objectives

After reading this chapter students should be able to understand:

• What key historical facts in the lead-up to World War II are emphasized by each perspective.
• What changes in those facts made war more likely, according to each perspective.
• How a collective security system (like the League of Nations) works.
• What the Treaty of Versailles’ intended effect on Germany was.
• What the main alternatives to balancing are.
• What possible explanations for overexpansion there are.
• What varieties of nationalism emerged after World War I and what their effect on the distribution of identities was.