Article: The interwar period was also marked by a radical change in the international order, away from the balance of power that had dominated pre–World War I Europe. One main institution that was meant to bring stability was the League of Nations, which was created after the First World War with the intention of maintaining world security and peace and encouraging economic growth between member countries. The League was undermined by the bellicosity of Nazi Germany, Imperial Japan, the Soviet Union, and Mussolini's Italy, and by the non-participation of the United States, leading many to question its effectiveness and legitimacy.

Now answer this question: Who undermined  The League Of Nations?
bellicosity of Nazi Germany, Imperial Japan, the Soviet Union, and Mussolini's Italy, and by the non-participation of the United States