The international community continues to take special interest in rebuilding nations following conflicts, but there is widespread concern about the sustainability of the changes arising from these interventions. This complex undertaking requires attention to multiple sectors, and the sustainability of any post-conflict reconstruction relies critically upon the strengthening of security and justice. Development is centrally concerned with creating and maintaining enabling environments, and these are undermined where there is instability or poor rule of law. The example of a large-scale intervention in Solomon Islands demonstrates that enhanced interaction between social, economic and security sectors is critical to sustainability. The divisions between these sectors must be transcended and priority given to security and justice in the early stages of intervention, to ensure durable change for vulnerable communities.