We celebrate great writers not only by reconstructing their ideas but also by thinking in their spirit. Many aspects of Raymond Aron’s legacy could, today, be exploited by writers of an Aronian turn of mind. They might draw on his philosophy of history; his defense of the specificity of politics; his acute awareness of the burdens of responsibility imposed on great powers. In this article, I flag a different topic: Aron’s concern with the impact of regimes and local cultures on political discussion. Of special interest to him were state-sponsored ideology and self-induced groupthink (the ‘opium of the intellectuals’). After briefly describing Aron’s views of both of these phenomena within the context of official and unofficial Marxism, I examine two modalities of communicative inhibition that have emerged since his death. Both turn on the emergence of Islamism as a major modern political ideology; both entail impediments to free speech: the vilification of political disagreement as ‘phobic’ and, relatedly, the political use of law (‘lawfare’) to halt debate on matters sensitive to Islamists.