Democratic societies are experiencing growing epistemic strain. Misinformation, polarisation, and fragmented information environments are weakening shared standards of evidence and the capacity for collective reasoning. Education policy has often responded by emphasising individual competencies such as critical thinking and media literacy. While important, this Element argues that such approaches are insufficient unless they are embedded within institutional conditions that allow ideas to be examined, contested, and translated into collective action. The Element introduces democratic intelligence: the collective capacity of institutions and societies to reason, learn, and act effectively under conditions of uncertainty and difference. It advances epistemic stewardship as a core responsibility of school leadership, focusing on the deliberate design of organisational conditions that enable engagement with trustworthy knowledge and structured professional dialogue. Across four sections, the Element shows how leaders can strengthen knowledge engagement, organise dialogue across difference, and translate collective reasoning into coordinated action and sustained school improvement.