The First and Second World Wars could almost be seen as the same war separated by a twenty-year break. The major participants were nearly the same and the results were similar. But the differences were very great. There was a major difference in the reasons for fighting the wars, there were significant changes in methods of fighting, the second war truly was global compared with the more local effects of World War I, and in the end the war changed the balance of power in the world.
Nationalist feeling was behind both wars. But there was a major difference in that feeling as expressed by the Germans under the Kaiser and under Hitler. In addition, the responses of the other nations varied accordingly. Though both wars were political there was a difference in aims. In the first war Germany, the Austro-Hungarian Empire, and Italy were primarily interested in expanding their influence and gaining territory. There may have been a feeling that the Germanic peoples were superior to others but proving this was not the primary reason for fighting. In addition to wanting to get control over certain relatively small areas in Europe the Germans wanted some of the rest of the world. They had been left behind after getting a late start in the race for colonies in Asia and Africa. France, Britain and even Belgium, Portugal and the Netherlands had done very well out of the international scramble for colonies. Defeating France, Britain and Russia in a war would help Germany and its ally Austria expand their influence in Europe and leave them in the position to lay claim to the colonial possessions of the losing nations. The Germans largely viewed both things as their right but this was based on their superior ability to get what they wanted -- not on the natural inferiority of their opponents.
The First World War was the last of the old-fashioned wars in which power alone, without ideological rationalizing, played the major role. S...