This thesis explores the relationship between state failure and intervention from a security governance perspective. Specifically, it considers the issue of the impact that the state failure thesis has had on the development of international law, specifically in regards to the practice of ‘non-intervention’ as this pertains to the jus ad bellum and the mandate and legal regimes governing post-conflict reconstruction. As such, there are three main chapters in this thesis. The first chapter examines how state failure has emerged as result of dynamic shifts in the international community since the establishment of the UN - with processes such as decolonization and the ascendance of human rights defining an era of international law that is much more receptive to intruding in the traditionally domestic domain of the state in areas that are pivotal to ensuring its security, stability, and capacity good governance. It then argues that, in this context, the concept of state failure - as an iteration of the 'state in crisis' model, should be recognized as a legal context and concept within the corpus of international law. The following chapters look at the relationship between ‘failed states’ and the international community through a military intervention context – highlighting specifically how the concept has defined the law relevant to counter-terrorism (ie. the issue of state-sponsorship of violent non-state actors, and the relationship between state failure and pre-emptive self defense), and how the state failure thesis has shaped the development of peacekeeping during the 1990’s and 2000s (specifically serving as the catalyst for its transformation towards a peace enforcement model). The final chapter examines the concept of statebuilding, and explores how it applies to the issue of state failure – both in situations of occupations and international territorial administrations. Its primary focus is on assessing the applicability of different post-conflict legal frameworks that apply to such operations – which include distinct but overlapping ideologies such as occupation law, peacebuilding, state-building, jus post bellum, and transitional justice – and outlines certain criteria necessary to make such determinations.