Answer:
Self-determination in general refers to the characteristic that brings nationalists together and form a new state and chose their government. Specifically in World War I, the idea of "self-determination" was aggrandized by US President Woodrow Wilson in his Fourteen Points for postwar healing, specifically referring to the Allies and repairing broken ties and intranational problems. It wasn't necessarily successful, however, until the United Nations came to be, since the League of Nations (the UN's predecessor) did not recognize the policy enough. It proved to be a failure when the Baltic territories of Russia as well as the Ottoman empire split.