The essay considers the meaning of conspiracy theory in state sanctioned politics in the Soviet sphere of interest during the First Cold War. At that time, Stalinist show trials, following the Moscow Purge Trials of the late 1930s, were transferred to East Central Europe. Show trials are no judicial lawsuits; there are performative acts as well as media events. They offer an elaborate and refined narrative— in order to destroy someone politically and morally by means of fabricated recriminations, but also as a means to reinterpret history in conspiratorial terms. Against the background of historical case studies from Stalinist Czechoslovakia and Eastern Germany, the essay focuses on two aspects which are related to the circumstance that conspiracy theories are meant to be disseminated amongst a given society: that, first of all, they are staged before a local audience and then, secondly, communicated—with the help of written texts, voice and visualization — to a wider audience outside the courtroom.