Despite the oft-repeated mantra that sustainable development requires security, and sustainable security requires development, international agencies and actors have struggled to reconcile peace and security with development concerns. Yet, in practice, a number of links and synergies have emerged, in most cases more by default than design. For example, from a narrow peacekeeping focus on separating well-defined parties under a negotiated ceasefire, multilateral peace and security operations have expanded to deal with irregular forms of war, up to and including peace enforcement operations, and to engage in the longer-term process of post-conflict peacebuilding, statebuilding and democracy promotion.1 The development community has also come to treat underdevelop­ ment as ‘dangerous’ and to invest in interventions to bolster governance and security in so-called fragile or weak states.2 This ‘mission creep’ was driven to some extent by institutional learning: a growing awareness of the ways in which warring parties (and the international actors) were caught in cycles of violent conflict and insecurity.3 In some cases, both development and security actors concluded that a failure to address effectively and comprehensively the immediate and underlying causes of armed violence meant that the embers smoul­ dered, waiting for the next spark to reignite into violence.4