Political wrangling earlier in 1933 had given Chancellor Dollfuss the opportunity to impose a form of post-democratic one-party government in Austria. There was a brief but savagely crushed civil uprising in February 1934 which had the effect of confirming the exclusion of the SDAP from national politics in Austria's new ""Austrofascist" "Ständestaat"". During 1934 Helen Postranecky was briefly arrested. The political activism in which, between 1934 and 1938, she continued to engage was now deemed illegal, and during this four-year period she was re-arrested several times, spending a total of eight months in prison. The political context then changed abruptly in March 1938 with the annexation of Austria into an Nazi German state. Postranecky now joined the illegal Communist Party. There was a widespread belief among Austrian Social Democrats that the Communist Party had foreseen and prepared for the Nazi take-over since the 1920s, and was therefore much better prepared to convert itself into a national underground anti-Nazi resistance movement that the SDAP. Postranecky was one of many making the political switch to the Communists in 1938. During the period between 1938 and 1945 she played a leadership role in "anti-fascist resistance".