Maintaining peace with adversaries can be costly, yet conflict models depict cooperation as a costless byproduct of not fighting. This article provides a formal model where peace may be costly and countries compete over bargaining surplus. Against conventional wisdom, repeated interactions of patient countries can destabilize peace without power shifts, as countries may prefer to "rip off the bandage." The likelihood of war depends on fundamentals of the international order, including outcome persistence and the severity of competition. Even when cooperation is mutually beneficial, wars are inevitable in the long run due to a coordination problem induced by costly peace. Competition over favorable settlements does not directly instigate attacks, but it reduces the gains from peace while counterintuitively making war less likely. The article offers new systemic explanations for war, highlights the importance of institutional design in conflict resolution, and sheds light on which international orders fare well over time.