For many on the extreme right, Scheidemann had become a personification of the hated republican, democratic system. They even coined the term "Scheidemänner" to use as a derogatory way of referring to the supporters of the Weimar Republic. On 4 June 1922, he was attacked with prussic acid (hydrogen cyanide), but escaped mostly unharmed. In December 1926, he exposed the clandestine cooperation between the Reichswehr and the Red Army. Since this was in violation of the Treaty of Versailles, the revelation caused the resignation of the third cabinet of Chancellor Wilhelm Marx.