This thesis is a theoretical and empirical inquiry into 'deliberative peacebuilding', seeking to explain the 'failures' and 'successes' of peacebuilding in East Timor and Somaliland. While warfare has increased globally since the end of the Cold War, the UN has made efforts to build peace (e.g. Boutros-Ghali 1992). While peacebuilding has become an internationally applied set of ideas and practices, one of the theoretical gaps is deliberation. This research thus conceptualises 'deliberative peacebuilding', and associates this with peacebuilding in the non-Western, post-colonial, and (post-)conflict context. This research identified East Timor and Somaliland as its case studies. Despite similarity in the 'legitimation problem' with vertical (state-society) and horizontal ('modernity'-'tradition') inequalities/differences based upon cultural and historical backgrounds, East Timor and Somaliland undertook different approaches in a decade after the end of their civil wars. While East Timor accepted UN peace operations, Somaliland rejected them. Yet both experienced similar transitions to make political order between 'failure' (political de-legitimation/societal dissent) and 'success' (political legitimation/societal consent).Accordingly, this thesis poses two questions: 1) what caused the UN to have 'failed' (to prevent the 'crisis' from recurring in 2006) in East Timor, and 2) what caused East Timor and Somaliland to have experienced 'equifinality' (making similar progress along different paths) in building peace (in East Timor from 1999 to 2012 and in Somaliland from 1991 to 2005). Findings, among others, include different paths in transition: a 'hybrid' path with external intervention in East Timor and an 'agonistic' path without it in Somaliland. Asymmetry in power relations urged deliberative agencies to address the 'legitimation problem' differently.