Why can nationalist movements lead to wars between states or groups?

Nationalist movements can lead to wars between states or groups because they often link the concept of a "nation" to the legitimacy of a "state," creating dangerous tensions when these two do not align.1

Key factors driving these conflicts include:

• Territorial Disputes and Irredentism: Because the ideal of a nation-state is rarely fully achieved, states often contain national minorities or have members living outside their borders. Irredentism—the attempt to reclaim or "redeem" territories inhabited by co-nationals—frequently leads to aggression and war.12
• Self-Determination Struggles: Groups that lack statehood may demand self-determination to form their own independent state. Majority groups often violently oppose these breakaway movements, leading to civil wars or international conflicts through foreign intervention.13
• Political Mobilization: Elites may use nationalist rhetoric to mobilize populations for political power, access to resources, or to divert attention from domestic problems.24
• Identity and Compromise: Nationalism can make compromise difficult by framing conflicts as existential struggles. When states identify with explosive differences in belief, the probability and intensity of war increase.14