Reply #25: kind of a short article in Wikipedia

[hfojvt]

I wonder if Ignatius Donnelly had some part in the creation. The Populist party was also somewhat socialist/prgressive. They also controlled some state legislatures around 1900 - in North Dakota and Kansas. They pretty much died as an independent party in 1896 when their Presidential candidate William Jennings Bryan also became the candidate for the Democratic party.
The socialist party was fairly strong before 1920, with socialist candidate Eugene V. Debs getting his highest percentage of votes in the 1912 Presidential election. He got 12% of the vote in places like Oklahoma, Kansas and Minnesota. The Federal government used the sedition act in WWI to clamp down on socialist leaders like Debs, sending him to federal prison for making speeches against the war. He still got almost a million votes in the 1920 election as Convict 9652.
However, a large part of it too was perhaps the post war prosperity of the 1920s made labor issues and socialism seem less relevant.