Out of the ashes of WWI: How viable was the idea of a World Parliament?

The League of Nations was founded to make the world a better place. Its aim was to stop the war, improve people's lives, disarm and enforce the Treaty of Versailles. However, it turned out to be useless, and there many reasons for its failure.
First of all, US, which were the country that came up with the idea of The League of Nations, did not join. It was the strongest country, and was the major power of the world, and they were very rich. For example, after the WWI, the economy of America went into a high speed development. From 1920 to 1929, the Gross National Product of Americans incre…