The peculiarities of the political perception of the phenomenon of "blooming complexity" are analyzed, which is actualized in the theory of the processuality of natural development in the teachings of K. Leontiev. An attempt is made to conceptualize the political foundations of the "blooming complexity" phenomenon. The basic scientific problem is the identification of characteristic features of the second phase - "blooming complexity", which fits into the triadic system of the birth, establishment and decline of states and civilizations in the theory of K. Leontiev. The results of the study are representative of the characteristics of the political features of each period of the system: primary simplicity, flourishing complexity, secondary confusing simplification - which appear in homologous unity and historically encapsulate a certain state-civilization in the general historical context. The concept of "blooming complexity" was scientifically reflected upon, in the process of consideration of which the ideas of the immanent despotic idea of the state, the concept of the real forces of society, the vision of K. Leontiev regarding the concepts of nation, nationalism, nationality, politics of foundations, etc., were articulated and worked out, as well as the peculiarities of the imperative of the social stratification A political revision of the historiosophical theory of development was carried out, according to which a certain state-civilization, passing through a three-phase process, is replaced by another. During the disclosure of the research topic, the principles of objectivity and impartiality were used, as well as the elimination of subjective evaluative judgments.