Hey everyone. Long-time lurker, first-time poster. I'm working on an idea for an alternate history scenario, and I thought this would be a good place to get some feedback on plausibility, options and such.
My idea is for the alliance between the German officer corps. and the SPD to collapse at the National Assembly in 1919 over the issue of army organization. As I understand actual history (Gordon A. Craig's Politics of the Prussian Army), intimidation of Ebert by Groener won a major victory for the traditional officer corps. at the National Assembly when the councils' wishes for army organization were not even brought up. In my timeline, the actions of the Freikorps raise a lot of resentment among the general population, who link them to the army, and in turn to the SPD where the theme of Ebert "betraying the revolution" is magnified. In the National Assembly elections, a much better-organized USPD manages to pull in a greater proportion of the working-class vote (somewhat more radicalized by right-wing violence) - not enough to form a government, but enough to push the Reichswehr vs. Volkswehr debate in the Assembly.
The vote either ends in a deadlock or in favour of the councils by a very slim margin as workers in the industrial west pressure their representatives in the Centre Party (the MSPD's 1919 coalition partners in this timeline - pretty sure they were in real life too, but not 100%) to abstain and deny the pro-Reichswehr camp the votes they need to secure the officer corps.' position. An outraged army leadership pulls out of the alliance with the MSPD (I'm not sure whether Groener was more of an ideologue or a pragmatist, but I think at this point it wouldn't matter - the army is going with or without him) and hatches a plot with the Freikorps to launch a false-flag attack disguised as a communist uprising in East Prussia, in order to give the army impetus to seize control of the country - in the short term for "national security", in the long term to "rescue" the "true" Germany (a-la von Seeckt) from the socialist rabble.
I'm already rambling too long here, so the summary of the end result is a Spanish-esque civil war in Germany between the army and right-wing in the north and east, and the socialists and councils in the south and west.
The major sticking point I can see from here is the issue of the working class being pulled left by Freikorps violence, military indifference, and Ebert's apparent non-support for workers' interests - namely because in the original timeline, the German general public found violence by the extreme left to be scarier. I think I would have to do something about the Sparticists.