This thesis makes an empirically grounded attempt to rethink the problem of ‘criminalization’— what it is, how it works, and the kinds of political work it performs—from the perspective of media culture. Informed by an abolitionist ethic, it explores the role played by news media in building, maintaining, and potentially transforming, the justificatory basis for different forms of security practice. More specifically, it investigates how journalistic representations of crime events work to negotiate, in and through public culture, the imaginative conditions of possibility for policing, incarceration, punitive deportation, and other strategies of so-called ‘crime control’. Its major theoretical contributions are a radically expanded understanding of what it means to culturally ‘criminalize’, as well as the ‘mediated security imaginary’ as a new critical heuristic for understanding the relationship between ways of communicating (in)security, on the one hand, and way of acting upon it, on the other. Together, these two contributions open new horizons (both scholarly and practical) for the cultural resistance of criminalization as an endemic, yet ultimately arbitrary, logic of contemporary social and political life. Empirically, these contributions unfold through a close analysis of one specific case of mediated criminalization: the construction of ‘African gang crime’ in and through the Australian press. Since beginning to arrive in Australia in significant numbers in the late 1990s and early 2000s, members of Australia’s Black African diaspora have been subject to persistent negative media attention, with news narratives focussing on perceived issues of juvenile delinquency and gang activity. The analysis approaches news media representations of ‘African gang crime’ events (both print and televisual) as sites of vulnerability politics, where different and sometimes conflictual accounts of social vulnerability struggle for public recognition. Deploying an ‘analytics of mediation’ (Chouliaraki, 2010) which combines granular multi-modal text analysis with the critical analysis of discourse (CDA), the thesis explicates how criminalization operates as a mediated politics of vulnerability across three key dimensions: first, through the negotiation of vulnerability as a political condition, or its constructed sense of “realness”; second, through the negotiation of vulnerability as a moral condition, or its constructed sense of “wrongness”; and finally, through the positioning of vulnerability as a practical epistemology of justification, or as a justificatory basis for different kinds of social practice. As the practices we have historically called criminal justice experience a moment of radical normative instability, this thesis argues that the mediation of criminality will have a critical role to play in determining its longer political legacy. To the wealth of political economy critiques of policing and prisons, the thesis accentuates ‘imaginability’ as an important critical horizon for our efforts to transform the practices through which we pursue safety and justice, and practices of mediated representation as crucial to how this horizon might be remade. Amid heated debates about the status of ‘the victim’ in contemporary political life, it also deploys a critique of mediated (in)security to consider the wider historical significance of a particular, premediated formation of white victimhood that expresses itself in a subjunctive mood: a victimcould, wherein it is the very possibility of injury (rather than the fact or the likelihood) that subverts the promises of whiteness in contemporary Australian life to position its subjects as ‘wronged’.