Agenda exit and policy closure: defensive governability‑making and housing tax reform in Australia (2014–2021)

Abstract Why do some policy agendas disappear not merely as a matter of declining attention, but as a consequence of becoming politically unsayable? Scholarship on policy processes has devoted extensive attention to agenda‑setting and non‑decision, but far less to the mechanisms through which once‑contested policy options are actively withdrawn from the space of legitimate political action. This article develops the concept of agenda exit to explain how policy contestation is stabilised when proposals become non‑viable to articulate and are subsequently constrained against return. Drawing on a process‑tracing analysis of housing tax reform in Australia from 2014 to 2021, the article shows how a coordinated field of property‑sector actors transformed electoral defeat into a durable agenda constraint through practices of reputational risk construction, substitution, and boundary‑policing. The core contribution is to theorise agenda exit as a condition of structured absence: an interregnum in which a policy remains technically conceivable but is rendered politically unsponsor‑able within ordinary arenas of contestation. This clarifies a distinct mode of policy stability, in which governability is secured not through consensus or resolution, but through the defensive narrowing of political possibility. By specifying how policy options become absent without formal decision, the analysis extends existing work on agenda control, blame avoidance, and policy continuity, and highlights the importance of studying the conditions under which policies can no longer be credibly proposed.