How does leverage vary across different mediator types and what influence does this have on mediation outcomes? Extant literature has glossed over the meaning of leverage, treating it as a static measure of material power. I argue that leverage is a dynamic concept comprised of two dimensions: capability and credibility. Capability leverage is a function of economic and military might while credibility leverage derives its influence from material, historical, religious, and cultural ties. I hypothesize that mediators with capability leverage will be more likely to achieve short-term success in the form of a negotiated settlement while mediators with credibility leverage will be more likely to achieve a more durable peace. I test my hypotheses using the universe of civil war mediation attempts from 1989-2006. My results suggest that capability leverage does indeed contribute to the achievement of a settlement while credibility leverage leads to more durable outcomes.