The League of Nations was Woodrow Wilson's vision for a new world order after the first world war. It was to provide for collective security and lower trade barriers. The League came into being but was a dead letter without America as a member, having collapsed amid political squabbling at home. It would take another, more deadly world war for some of Wilson's ideas to be put into practice, eventually through the United Nations and the Bretton Woods system.
Whenever someone tells you to take their advice, you can be pretty sure that they're not using it.