This edition of the 'SIPRI Yearbook' analyses developments in 2016 in security and conflicts; military spending and armaments; non-proliferation; arms control; and disarmament.

This volume brings together expert case studies on a range of experiences of third-party interventions in civil wars. The chapters consider the role of a variety of organisations, including the United Nations, NATO, the European Union, the Shanghai Cooperation Organisation, the Organisation of the Islamic Conference, the African Union, and the Organization of American States. Each case study features a presentation and analysis of empirical data in two dimensions: the organisation’s general capabilities to carry out intervention in civil wars and, specific to one particular intervention, the conflict context in which it happened. This serves two purposes. First, to offer insights into the dynamics of each individual case and helping us understand the specific outcome of an intervention effort, i.e., why did a mission (partially) succeed or fail. Second, it enables us to make real comparisons between the cases and draw policy-relevant conclusions about the conditions under which military, civilian and hybrid intervention missions are likely to succeed. This book was originally published as a special issue of Civil Wars.

This book identifies the conditions under which foreign countries intervene in civil wars, contending that we should consider four dimensions of civil war intervention. The first dimension is the civil war itself. The characteristics of the civil war itself are important determinants of a third party’s decision making regarding intervention. The second dimension is the characteristics of intervening states, and includes their capabilities and domestic political environments. The third is the relationship between the host country and the intervening country. These states’ formal alliances and the differences in military capability between the target country and the potential intervener have an impact on the decision making process. The fourth dimension is the relationship between the interveners. This framework of four dimensions proves critical in understanding foreign intervention in civil wars. Based on this framework, the model for the intervention mechanism can reflect reality better. By including the relationships between the interveners here, the book shows that it is important to distinguish between intervention on the side of the government and intervention on behalf of the opposition. Without distinguishing between these, it is impossible to consider the concepts of counter-intervention and bandwagoning intervention.

This book investigates the extent to which traditional international law regulating foreign interventions in internal conflicts has been affected by the human rights paradigm. Since the adoption of the Charter of the United Nations, foreign armed interventions in internal conflicts have turned into a common practice. At first sight, it might seem that state practice has developed in a chaotic fashion, however on closer examination, specific patterns emerge. The book charts these patterns by examining the traditional doctrines of intervention and testing them against state practise. The book has two aims. Firstly, it seeks to clarify the current legal framework regulating interventions in internal conflicts. Secondly, it plots the emergence of new trends and investigates whether they are becoming part of positive international law. By taking this dual focus, it offers the first truly comprehensive examination of foreign interventions in internal conflicts.

Intervention in armed conflicts is full of riddles that await attention from scholars and policymakers. This book argues that rethinking intervention—redefining what it is and why foreign powers take an interest in others' conflicts—is of critical importance to understanding how conflicts evolve over time with the entry and exit of external actors. It does this by building a new model of intervention that crosses the traditional boundaries between economics, international relations theory, and security studies, and places the economic interests and domestic political institutions of external states at the center of intervention decisions. Combining quantitative and qualitative evidence from both historical and contemporary conflicts, including interventions in both interstate conflicts and civil wars, it presents an in-depth discussion of a range of interventions—diplomatic, economic, and military—in a variety of international contexts, creating a comprehensive model for future research on the topic.

Some of the most brutal and long-lasting civil wars of our time involve the rapid formation and disintegration of alliances among warring groups, as well as fractionalization within them. It would be natural to suppose that warring groups form alliances based on shared identity considerations - such as Christian groups allying with Christian groups - but this is not what we see. Two groups that identify themselves as bitter foes one day, on the basis of some identity narrative, might be allies the next day and vice versa. Nor is any group, however homogeneous, safe from internal fractionalization. Rather, looking closely at the civil wars in Afghanistan and Bosnia and testing against the broader universe of fifty-three cases of multiparty civil wars, Fotini Christia finds that the relative power distribution between and within various warring groups is the primary driving force behind alliance formation, alliance changes, group splits and internal group takeovers.