Subsequently, the Social Democratic Party and the newly founded Communist Party of Germany (KPD), which consisted mostly of former members of the SPD, became bitter rivals, not least because of the legacy of the German Revolution. Under Defense Minister of Germany Gustav Noske, the party aided in putting down the Communist and left wing Spartacist uprising throughout Germany in early 1919 with the use of the Freikorps, a morally questionable decision that has remained the source of much controversy amongst historians to this day. While the KPD remained in staunch opposition to the newly established parliamentary system, the SPD became a part of the so-called Weimar Coalition, one of the pillars of the struggling republic, leading several of the short-lived interwar cabinets. The threat of the Communists put the SPD in a difficult position. The party had a choice between becoming more radical (which could weaken the Communists but lose its base among the middle class) or stay moderate, which would damage its base among the working class. Splinter groups formed: In 1928, a small group calling itself Neu Beginnen, in the autumn of 1931, the Socialist Workers' Party of Germany. The Iron Front, founded in December 1931, was not a splinter party but a nonpartisan association led mostly by the SPD.