The winners of World War II attempted to avoid what three mistakes made by the winners of World War I?

1. After WWI, the Allies tried to just use laws/treaties to keep Germany from becoming strong again and from causing another war.  This failed. After WWII, they tried to take a different tack.  Now, the Allies occupied both Germany and Japan.  They did not let those countries go back to ruling themselves for years. Instead, they controlled the former Axis powers and tried to remake their societies.  In Germany, they tried to purge Nazis from power. In Japan, the US introduced a new constitution.  In this way, they tried to make sure that Japan and Germany would not disrupt the peace in the future instead of just hoping that laws and treaties would make this happen.


2. After WWI, the Allies created the League of Nations, but did not do a very good job of it.  Most notably, the US failed even to join the League. The League was, therefore, very weak. After WWII, the victors created the United Nations.  This was a much stronger and more effective version of the League of Nations. In other words, the Allies learned from their previous mistakes and understood that they needed to create a body that would be stronger and more effective.


3. After WWI, the victors essentially divided up the territories that had belonged to Germany.  They ostensibly placed those territories under League of Nations mandates, but, in essence, the victors just took the territories for themselves.  After WWII, this did not happen as much.  Korea became independent.  Taiwan returned to China and then became semi-independent.   Parts of China that Japan had held returned to China.  This made it seem less as if the Allies had fought the war as a way to gain territory.

The Allies did all these things because they wanted to avoid making the same mistakes they had made after WWI.