This thesis is a critique of liberal humanitarian representations of violence in the context of Post-Conflict or Post-Authoritarian struggles against impunity. In particular, it addresses the argument of "cultures of impunity" whereby punishing perpetrators of violations of human rights in transitional societies prevents the endorsement of regimes of silence and the normalisation of wrongdoing. Drawing on a Deconstructivist and Disciplinary methodology this thesis argues that debates about punishment or forgiveness in the aftermath of systematic violence have a wider political meaning and a particular historical function. Instead of mere responses to an external reality "punishment vs. impunity" debates also have a productive facet: because they represent violence in a liberal humanitarian frame, they produce a postconflictual ethos that defines (1) the modes of acceptable political resistance in the present and (2) the achievable limits of justice in the future. In order to explain this wider "politics of impunity" this thesis focuses on the Brazilian transitional case, from the end of the Dirty War in the 1970s to the establishment of the National Truth Commission (2012-2014). As such, it rejects the explanation of Brazil as a quintessential "culture of impunity," a reasoning that blames the amnesty of perpetrators after the militarised dictatorship (1964-1985) for instituting a regime of silence about the past and creating the conditions for an eternal state of exception in Brazil. Although it recognises the merits of this logic, this work argues against it, reassessing the question in a rather different perspective. First, the thesis suggests a methodological twist: moving focus away from the conditions of implementation of justice in post-conflict and post-authoritarian scenarios into the conditions of possibility of the promise of "never again". This thesis analyses truth commissions, criminal tribunals, and reparation programmes as parts of a historically situated set of disciplines; that is, as the conjunction between a body of knowledge and modes of conduct centred on a specific representation of violence as an intentional, cyclical, and exceptional phenomenon. In other words, it is by narrowing down what violence is that struggles against impunity can promise a future of non-recurrence. Second, the thesis then describes how this representations of violence were mobilised in order to historically produce a postconflictual reality in Brazil. By analysing the trajectory of the memory struggles (1975-) I explain how this postconflictual reality redefined the meaning of political resistance after the Dirty/Cold War, and by looking at the work of the truth commission I describe in what sense it creates a parsimonious promise of justice.