<P> After some notable successes and some early failures in the 1920s , the League ultimately proved incapable of preventing aggression by the Axis powers in the 1930s . The credibility of the organization was somewhat weakened by the fact that United States never officially joined the League and the Soviet Union joined late and only briefly . Germany withdrew from the League , as did Japan , Italy , Spain , and others . The onset of the Second World War showed that the League had failed its primary purpose , which was to prevent any future world war . The League lasted for 26 years ; the United Nations ( UN ) replaced it after the end of the Second World War and inherited several agencies and organisations founded by the League . </P>
when did the league of nations become the united nations
after the end of the Second World War