The aim of this paper is to explore the inner logic and systematic structure of Schmitt's legal-political thought between 1912-1933. I argue that Schmitt's legal thought belongs to the type he called ”decisionism” and that the development of his decisionism is determined by the starting point of his legal studies, namely Rechtsverwirklichung and Rechtspraxis. Starting from ”decisionism of Rechtspraxis,” Schmitt develops his decisionism step by step to what may be called ”decisionism of sovereignty” and ”decisionism of the political”. From a systematic point of view, each development offers a basis for the earlier developed thought and all these three parts form an autonomous ”type” of legal thought.