Unlike interstate wars, civil wars rarely end in negotiated settlements. Between 1940 and 1990 55 percent of interstate wars were resolved at the bargaining table, whereas only 20 percent of civil wars reached similar solutions. Instead, most internal wars ended with the extermination, expulsion, or capitulation of the losing side. In fact, groups fighting civil wars almost always chose to fight to the finish unless an outside power stepped in to guarantee a peace agreement. If a third party agreed to enforce the terms of a peace treaty, negotiations always succeeded regardless of the initial goals, ideology, or ethnicity of the participants. If a third party did not intervene, these talks usually failed.