Peacemaking in a New World offers a macro-level perspective on how world orders shape peace processes, arguing that the standard mediation model of 'consent-based conflict resolution', developed in the post-Cold War era, is in crisis. Through the case study of UN mediation in Syria, the book demonstrates how the material and ideational features of the new world order - geopolitical competition and normative contestation - undermine this model in two ways. First, conflict parties are less willing to consent to mediation, as they increasingly prioritize military over political solutions. Second, conflict resolution gives way to conflict management, as the UN is progressively sidelined in peacemaking efforts. The book highlights a central dilemma UN Special Envoys face in this new world: while conflict resolution remains their main comparative advantage in fostering conflict parties' consent, it is precisely what they are compelled to compromise on to secure consent in the first place. It concludes by suggesting a path forward for the UN, comprising modesty and courage. Modesty, in redefining its role away from leading peace processes towards providing mediation support, legitimizing agreements, and guaranteeing implementation, and courage, in defending universally-endorsed values, embracing a whole-of-UN approach, and broadening the very definition of peace processes. This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read at Oxford Scholarship Online and offered as a free PDF download from OUP and selected open access locations.