An idea occurred to me the other morning. Now, I don't think this is possible with a PoD after 1900, so that is why I post it here. I was thinking about the two party system we have here in the US and thought back to some old local newspaper articles I was researching from WWI. What sort of PoD would it take for the US to have more than two parties represented in Congress (and I am talking about something more than the occasional independent who is either Democrat or Republican in all but name)? Specifically, at least for the first third to half of the twentieth century for these to be the major parties:
-Republicans
-Democrats
-Populists
-Bull Moose Progressives
-American Labor Party (I know it was floated around in union circles during the 1900s but the unions ultimately rejected the idea of forming a political party)
The Democrats and Republicans would be the two largest parties beyond a doubt, as they were IOTL, but the "half-party"/kingmaker role would alternate between Labor, Progressive, and Populist. Now these parties don't need to continue to exist until the present day- other parties could take their place. How would this effect US politics and policies in the long term and I wonder how the parties would adapt, or not, to changing social pressures.
This is my first thread here, so I'm still learning the ropes, fyi.