This article attempts to comprehend the process of moderation of the Islamic Left – the progenitor-faction of the Reformists. In the changed global context and socio-political landscape of the Islamic Republic of Iran in the 1990s, the Islamic Left could not rapidly adapt to the new environment which diminished their appeal among the constituency. The erosion of public trust enabled the Right to push their rivals aside using the Guardian Council as a political filter, and soon the Left found themselves on the margins of mainstream politics. However, during this enforced isolation, they managed to reassess their post-revolutionary experience, and their political platform underwent a significant transformation. The new think-tanks and intellectual circles, most notably the Center for Strategic Studies and the “Keyan” circle, played an instrumental role in this process. Within this intellectual infrastructure, a new religious and political discourse emerged, providing argumentation for a rethinking of R. Khomeini's legacy from the standpoint of republicanism. Then the elitist language and vague ideas of this discourse were politicized and disseminated through the network of like-minded media. The slogans of the “New Left” gained wide support among the youth and the urban middle class, who advocated the development of political pluralism and the continuation of the course of economic liberalization and detente, which had begun during the tenure of the President A.A. Hashemi-Rafsanjani (1989–1997). These strata formed the core social forces that ensured the victory of Mohammad Khatami in the 1997 presidential elections, and then supported the Reformist “May 23rd Front”.