The League of Nations played a crucial role in early 20th-century international politics by attempting to maintain peace and prevent conflicts through diplomacy and collective security. Established after World War I through the Treaty of Versailles, the League aimed to facilitate cooperation among member nations and to resolve disputes without resorting to war. However, it struggled with enforcement and lacked participation from key powers, including the United States. Consequently, its inability to prevent aggression leading up to World War II led to criticism and its eventual dissolution, paving the way for the creation of the United Nations.