Why did the united states decide not to participate in the league of nations established by the treaty of versailles at the end of world war i?

Joining the League of Nations would be like signing a blank cheque - America didn't want to have to ship its troops half way across the world for disputes that didn't concern them. It didn't want to risk its economy or any more American lives after the losses of WW1. The Republicans wanted to return to Isolationism - being an independent country and not involving itself in other countries affairs. America also strongly disagreed with the Treaty of Versailles.