Pancasila, Indonesia’s state philosophy, was presented by Soekarno in 1945 as a framework capable of uniting the nationalist, Islamist and Marxist streams of the independence movement. This article argues that it has far more often functioned in two other ways: as an assertive, prescriptive ideology imposing a single political vision, most clearly under Guided Democracy, and as what Donald Porter (2002) calls an “ideology of exclusion and containment,” most clearly under the New Order. Tracing these models from the 1945 debates through the New Order to the ‘repressive pluralism’ of the Jokowi era, the article shows that neither prevented the major political conflicts of Indonesian history. It then identifies a third, ‘open’ model grounded in Soekarno’s own early statements, under which different groups could interpret Pancasila according to their own worldviews while debating through its shared language. Drawing on the recent acceptance of Pancasila by previously rejectionist Islamists, the article contends that an open approach to Pancasila offers a path towards unity through diversity, whereas renewed exclusion risks pushing Islamists back towards disengagement or violence.