The primary difference between the United Nations and the League of Nations is their effectiveness in promoting peace, with the UN being more successful due to its broader membership and enforcement capabilities. The League, established in 1920, struggled to maintain authority and enforce decisions, while the UN, founded in 1945, encompasses a wider range of issues and includes major world powers. Therefore, effectiveness is the chosen answer.
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The primary difference between the United Nations and the League of Nations is their effectiveness, stemming from the League's limited participation and enforcement capabilities compared to the UN's broader mission and inclusion of key global powers. While both were created to promote peace, the UN has proven more effective in addressing international issues. Therefore, effectiveness is the most fundamental distinction between the two organizations. ;