The effectiveness of mediation and peacekeeping for ending conflict

Abstract Mediation and peacekeeping are commonly used tools to manage conflict. To what extent are they complementary and effective instruments for ending violent conflicts? Generally, they are seen as distinct tools: mediation aims to facilitate negotiated settlements, while the goal of peacekeeping is to prevent agreements from collapsing. However, peacekeeping and mediation regularly occur simultaneously. Arguably, peacekeeping operations rely on continuing political processes, while peacekeepers create a context favorable for mediation and provide a valuable source of independent information. Using a variety of model specifications, including selection models, empirical evidence supports that (a) mediation rather than peacekeeping is key to halting hostilities, (b) mediation and peacekeeping are largely complementary, but (c) this complementarity is conditional: in the post-Cold War period, transformative peacekeeping boosted the effectiveness of mediation to halt civil wars. There is no evidence that peacekeeping on its own matters for ending conflict. Finally, counterfactual analysis shows the substantial impact of mediation and peacekeeping on the frequency of conflict.