Politics or Performance? Leadership Accountability in UN Peacekeeping

International organizations face a trade-off between the need to replace poorly performing leaders and the imperative of preserving the loyalty of influential or pivotal member states. This performance-politics dilemma is particularly acute in UN peacekeeping. Leaders of peacekeeping operations are responsible for ensuring that peacekeepers implement mandates, maintain discipline, and stay safe. Yet, if leaders fail to do so, is the UN Secretariat able and willing to replace them? We investigate newly collected data on the tenure of 238 civilian and military leaders in thirty-eight peacekeeping operations, 1978 to 2017. We find that the tenures of civilian leaders are insensitive to performance, but that military leaders in poorly performing missions are more likely to be replaced. We also find evidence that political considerations complicate the UN's efforts at accountability. Holding mission performance constant, military leaders from countries that are powerful or contribute large numbers of troops stay longer in post.