How did decolonization after World War II increase the number of sovereign states?

After World War II, the number of sovereign states increased dramatically as the global decolonization movement dismantled European overseas empires. This process was driven by several key factors:12

• Promotion of Self-Determination: The United Nations made the principle of self-determination a central goal, explicitly facilitating the transition of dependent territories to independence.34
• Shifting Geopolitics: The emergence of the United States and the Soviet Union as superpowers created an environment where traditional colonialism became increasingly untenable. Both superpowers generally opposed old-style European colonialism, often preferring indirect influence.1
• Economic and Political Costs: War-weary European nations, facing economic strain and mounting pressure from mass revolutionary movements in their colonies, found the financial and political costs of maintaining overseas empires unsustainable.15
• Diplomatic Momentum: By the late 1950s and 1960s, anti-imperialist sentiment made colonialism globally unacceptable, leading to the establishment of new states in Africa and Asia on an almost monthly basis.2

These newly independent nations often became fiercely protective of their sovereignty, territorial integrity, and noninterference in internal affairs.2