What major Allied power refused to join the League of Nations following the end of World War I? France Great Britain United States Russia

The answer is United States.

The League of Nations came into being after the end of WWI. The task of the League of Nations was simple - to ensure that war never broke out gain.

American President Woodrow Wilson was particularly horrified by the slaughter that had taken place in what was meant to be a civilized part of the world. The only way to avoid a repetition of such a disaster was to create an international body whose sole purpose was to maintain world peace and which would sort out international disputes as and when they occurred.

Support for the idea was great except in America where isolationism was taking root, and true to this, America, whose president Woodrow Wilson, had dreamt up the idea, refused to join it.

Germany was certainly not invited, and Russia was not allowed to join because she had a communist government at the time.