Celebrating the new Constitution, ratified in January 2014, a political commentator close to secular circles declared: ”it is a success for Tunisia. We have succeeded in ”tunisiafying” An-Nahda while Islamists have failed to islamize Tunisia”. This declaration put forward the sheer magnitude of conflicts opposing the secular movement to the governing An-Nahda party. Indeed, the former consider Political Islam as exogenous to the nation, when the latter ceaselessly reassert their attachment to national unity while displaying unwavering ambiguity with regards to the movement’s religious identity. De facto, the consensus leading to the Constitution’s ratification was perceived by the secular opposition as the sign of Islamists’ conversion or adherence to a tunisianess”, whose boundaries however remain ill-defined. Conflicts between Islamists and the secular opposition provide an interesting entry-point into the reinvention of a republican Islam, which should be analyzed in light of the Tunisian political trajectory and of decades-long societal “re-islamization”. Far from being the result of a shared vision or some conformity of thought, let alone of intellectual convergence, the consensus and the Constitution that derived from it was rather the result of ambiguities and ambivalences that are nonetheless operational. The alliance with secular parties, the acceptance of compromises and the confrontation with the political, social and religious developments in the new Tunisia, have progressively transformed An-Nahda into a governing party, which should be further analyzed, not only from the simple scope of Islam but rather considering the political trajectory, the historical legacies and economic, social and religious changes that Tunisia has experienced. Thanks to interviews conducted with political actors involved in Tunisia’s national dialogue as well as in process of Constitution-drafting, this work aims at unfolding the transactional dynamic during the transition, and whose stake does not solely lie in the renegotiation of the relationship between the religious and the political in the post-Ben Ali era, but also encompasses the completion of a « negotiated integration » and normalization of An-Nahda within Tunisia’s political system. Breakthroughs in the transition process should hence be put to the credit of the Islamist movement’s ambivalences and ambiguities, rather than to the emergence of culture of consensus within the Tunisian political community. An ambiguity which, paradoxically, is likely to steer secularization forward.