Looking back over the past seventy-five years of UN peacekeeping, the most enduring question has been: Is peacekeeping effective? Historically, most peacekeeping operations have been. However, peacekeeping is currently suffering from a significant trust deficit. One important factor that differentiates contemporary peacekeeping operations with a stabilization mandate from the historic record is the absence of a viable political or peace process. When security is not directed to serve a peace process, it produces a stabilization dilemma: the more effectively a peace operation protects and achieves stability, the less incentive there is for ruling political elites to find long-term political solutions. This dilemma generates several perverse effects, including prolonging the conflict, trapping operations in place with no exit options, increasing the resilience of armed groups, and embedding peacekeeping in the local political economy. The article identifies five factors that help prevent the stabilization dilemma and influence the effectiveness of peace operations. [ABSTRACT FROM AUTHOR]