In January 2016, late in his term as Secretary-General, Ban Ki-moon introduced a Plan of Action to Prevent Violent Extremism (PVE). The approach promised to bring balance to multilateral counterterrorism by adding much-needed focus on the drivers of mobilization into violence. Highly arguable in theory and with great potential against the online recruitment efforts of groups such as Islamic State in Iraq and Syria, the PVE agenda has nonetheless found enemies at the United Nations—both among member states and within the Secretariat. Errors committed in the Plan of Action’s rollout made the new approach hostage to the very limitations and tensions that it was intended to resolve. PVE also rests on a shaky conceptual foundation and has been further stultified by the intensely political setting in which it was to be implemented. The future of this well-intended approach therefore looks at risk, even bleak. This article traces and explains the rise and likely fall of PVE at the United Nations, bringing to light a number of sobering insight into the possibilities and limits of multilateral counterterrorism.