The premise is that under the Allied occupation all of the Weimar Era states are duly restored, including the legal Prussian government under Otto Braun (something Allies declined IOTL, deciding to abolish Prussia altogether). Germany still loses the same land to Poland and the Soviet Union but because the core of Prussia, Berlin-Brandenburg, remains behind the Oder-Niese line, the Braun administration is allowed to continue.
Things changes with the establishment of the West and East German States in 1949, as each state adopts their respective RL political systems. In the West, Prussia is being split by making each remaining province a separate Land. It is only after the reunification that Prussia is, for whatever reason, being restored as a constituent state.
In the West, Weimar-era parties were reconstituted, with the failure to unite conservative Catholics and protestants into one Christian Democratic party. Kurt Schumacher wins the first election, heading a SDP-DDP coalition government, and Adenauer fells into a political abyss.
As communism ends in the East, SED reconstitutes itself into a "new" USPD.
Now, if someone is brave enough, post a list of Chancellors (and maybe Presidents too), starting with Schumacher, and maybe come up with contemporary politics of these alternative German lands
