The major thesis of this essay, firstly published in Sociological Theory, 1998, vol. 16, No. 6, is that fragility and instability are inherent to constitutional democratic regimes, and are rooted in (1) ideological and institutional history of modern political formations, (2) the tensions between different conceptions of democracy (especially between constitutional and participatory democracy) and (3) the central aspects of the cultural and political program of modernity. The common core of these premises is the openness of the political process (particularly with regard to protest movements) and the concomitant tendency toward continual redefinition of the political realm. In the first part of the essay, published in this issue, the author investigates the crystallization of the cultural and political program of modernity, analyzes the innate antinomies and tensions proper to this program, and discusses two complementary, but also potentially contradictory conceptions of democracy - the constitutional and the participatory. The author demonstrates that both these conceptions and their institutional implications have been inherent in the very construction, crystallization, and dynamics of modern constitutional democratic regimes and are rooted in the historical-ideological background of the modern cultural and political program and the contours of the modern state.