The treaties signed at the Paris Peace Conference had created some new states and changed the borders of other existing states. However, these new boundaries might split a community, putting some people in one state and the rest in another. It was the job of the League to sort out border disputes and it did this well. An example of this was Upper Silesia in 1921. This was an industrial region on the border between Germany and Poland and both German and Polish people inhabited it. Both Germany and Poland wanted control of it so in 1920, a plebiscite was organised for Silesians to vote on which country they wished to join. The industrial areas voted mainly for Germany, the rural areas mainly for Poland. The League therefore divided the region along these lines but they built in many safeguards to prevent future disputes. Furthermore, another incident was that of the Aaland Islands in 1921. Both Sweden and Finland wanted control of the Aaland Islands, which were midway between the two countries. Both countries were threatening to fight for them. They appealed to the League and after studying the matter closely, the League said that islands should go to Finland. Sweden accepted the League's ruling and war was avoided.
In the 1920's, it is safe to say that the League failed in bringing about disarmament. At the Washington Conference in 1921 Japan, USA, Britain and France agreed to limit the size of their navies, but that was as far as disarmament ever got. In 1923, the League's first attempt at a Disarmament Treaty was accepted by France and by other nations, but was rejected by Britain because it would tie it to defending other countries. In 1926, plans were finally made for a Disarmament Conference but it took five years even to agree a "draft convention" for the Conference and in 1933 that was rejected by Germany. The failure of disarmament was particularly damaging to the League's reputation in Germany.
