This talk argues that commitment problems in the construction of power-sharing arrangements tend to make civil conflicts all or nothing fights for control of central or regional government. An implication is that civil wars will tend to end with military victory occasioned by a shock to one side's relative power or cost tolerance. Researchers coded the 119 terminated civil conflicts listed by the Political Instability Task Force using a new scheme that recognizes conceptual differences in the meaning of military victory and negotiated settlements for civil wars where the rebel groups seek power at the center versus in a region. Findings were that power-sharing is quite rare in center-seeking wars, and somewhat more common in separatist conflicts (in the form of regional autonomy agreements). Finally, researchers examined case narratives for 30 randomly selected conflicts. Findings were that shocks to relative power in the form of entry or exit of foreign support for one side commonly caused civil war termination. Findings also showed some evidence that changes in government leadership, possibly the result of shocks to cost tolerance, associates with civil war termination in our set of random narratives.