Since the Cold War and especially after the attacks of September 2001, security sector reform has become a key component of the state-building project targeting unstable, fragile states. Yet, despite its popularity with donors and other international stakeholders, SSR has often failed to fulfill its overarching objective: reduce violence and make people safer. SSR success is unclear at best, as suggested by Afghanistan and Iraq, but also Haiti and El Salvador. In this dissertation, I argue that SSR falls short of its promises because it often fails to acknowledge the complex environment in which it takes place. Indeed, SSR tends to remain state-centric, targeting only public security and justice institutions and their formal role in the production of public order. Yet, in fragile states, the State does not hold the monopoly on violence, and its capacity to produce public order and provide security remains limited. Where the State is unable to do so, other actors have often emerged to produce public order and claim control over the means of violence.
To better understand the impact of SSR on these complex environments, I introduce the public order regime framework to map out systematically how public order is produced by state and non-state actors through more or less formal means in those complex polities. Looking more closely at SSR programs in Haiti and El Salvador, I find that the effect of SSR on pluralist public order regimes varies based on the strategy chosen to deal with non-state coercive actors and informal public ordering. Where non-state actors have a strong incentive to claim control on the means of violence, state-centric SSR tend to be disruptive and can backfire, increasing rather than reducing violence. When the structure of the regime is taken into consideration by SSR however, the disruptive consequences of these reforms can be mitigated. Based on those results, I call for a more pragmatic approach to SSR that departs from Western normative assumptions, and is anchored in a finer understanding of the complex composition of governance structures in fragile states.