Why had international Peace collapsed by 1939? Hitler came to power in 1933. In 1942 he wrote a book entitled "Mein Kampf" describing what he would do if the Nazis ever achieved power in Germany. When Hitler did come to power he has 3 main aims. Hisfirst was to abolish the treaty of Versailles.
He believed that the treaty was unjust and he hated it because it reminded him of their defeat in WW1 and their humiliation by the allies. Hitler promised that if he came to power then he would reverse this. He also wanted to expand German territory because the treaty had taken land away form them after the First World War.
He wanted more "living space" for Germans, and wanted Austria to join with Germany and for German minorities in other countries like Czechoslovakia to rejoin Germany. Hitler hated communism and he wanted to get rid of it. He believed that they helped bring the defeat of WW1 and believed that they wanted to take over Germany.
To be sure that they didn't Hitler wanted to remove them once and for all. The League of Nations were set up in the 1920s so that each country could feel protected after the war and it would be like a world parliament to keep the peace and sort out any problems. In the early 1930s there were two main tests for the league; The invasion of Manchuria and Abyssinia. The Japanese invaded Manchuria in 1931. Japan had a very strong army, it had a strong industry and a growing empire. They wanted to expand Japanese territory after the causes that the depression had on them.
China appealed to the league for help but Japan claimed that they were just trying to sort out a localdifficulty. For the league this was a serious test because Japan was one of their main leading powers therefore they needed to handle the situation very carefully because they were risking losing Japan. After a year the league decided that Japan was in the wrong and Manchuria should be given back to China. Howe.