[Page 795]The term spoiler was first used by political scientist Stephen J. Stedman in the 1990s to refer to a leader or a party whose power, interests, or worldview are threatened by a peace process and who therefore decide to use violence to spoil the peace. In Stedman’s typology, spoiler types depend, in part, on sensitivity to costs and risks. Thus, spoilers and spoiling are bound with debates over the rationality of political decision making. After a brief summary of Stedman’s typology, this entry will review debates over the identification of spoilers and would-be spoilers as well as over the reasons behind spoiling behavior.