In an attempt to make sense of changes and continuities of the Algerian regime, this thesis tests the following hypothesis - the sense of belonging to the same polity is a background condition for democratization processes to succeed - through the analysis of two periods of transition in Algeria: a period of transition from below, from 1988 to 1991, and a period of transition imposed from above from 1995 to 1998. The analysis of the first period shows the mechanisms through which the existence of two factional opposition tendencies in the political arena has an impact on transition. At the beginning of the transition, the opposition, whether factional or tolerant, found in soft liners in the regime informal allies to push for more opening leading to the organization of founding legislative elections in December 1991. However, after the first round of legislative elections, it appeared that the Islamist factional opposition, the FIS, had won the majority of the votes. Under such conditions, part of the democratic tendency, feeling threatened by the outcome of the legislative elections of 1991, called for their cancellation. By calling on the hard liners in the regime to stop the process of democratization, they weakened the soft liners’ position in the regime and lowered the costs of a coup and the repression of the FIS. In short, the informal alliance between hard liners in the regime and part of the democratic tendency led to the January 1992 military coup which marked the failure of the first period of transition in Algeria. The analysis of the second period of transition shows the mechanisms through which soft liners broadened the authoritarian regime’s social base without becoming entangled in the unstable and perilous dynamic of liberal reform. It is argued that, under conditions of a threat posed by the factional FIS, elections become procedures allowing soft liners in the regime to coopt a “moderate Islamist” party in order to broaden their social base. The legislative and local elections organized in 1997 is analyzed as a process of putting into practice the legal institutionalization of moderate Islamism through the co-optation of a “moderate Islamist” party, namely the MSP-Hamas party. In doing this, this thesis sheds light on the Algerian authoritarian regime’s survival albeit in an allegedly more liberal and democratic form.