In considering the first half of the twentieth century with an emphasis placed on the changing realities of nationalism, how was the world a...

By the end of World War II in 1945, nationalism in Europe had earned a bad name for itself, as Fascists such as Hitler and Mussolini had used nationalism to rally their countries to go to war and engage in atrocities. The United Nations, founded in 1945, is an international peacekeeping agency that was created to try to prevent future wars through cooperation. In the western zones of Germany and in Japan, the Allies rebuilt those nations' infrastructure and economies, fostering a spirit of international cooperation rather than fervid nationalism.

In this way, the world in 1945 was different than the world of 1919, in which nations that had been punished for World War I, such as Germany, developed a defensive sense of nationalism, and other nations wanted to punish Germany for the war. In addition, the League of Nations, the pre-cursor to the United Nations, largely failed, as the United States refused to become a signatory. 

However, it is false to think that World War II did not ignite nationalist feeling. In the developing world, including India, Africa, the Middle East, the Caribbean, and other places, nationalist movements developed in the aftermath of the war (and some had developed even before the war) that shook off imperialist powers, most notably England and France, in favor of home rule.