The relationship between economic interdependence and international conflict is a burgeoning research topic. Previous research has examined the role of interstate conflict on bilateral total trade. Civil wars also have severe consequences on society and are not uncommon. This article seeks to shed light on this relationship by examining the impact of civil war in one country on the total bilateral trade between the afflicted state and its trade partners. The repercussions of civil war participation on a militarily intervening third party’s trade also receive scrutiny. Furthermore, the outcome of the civil war is investigated to determine whether all war terminations have the same effects on trade. Finally, this article questions whether the effects of civil wars can be mitigated by security partnerships. One key finding from analyses of 120 countries between 1950 and 1992 is that civil wars decrease bilateral trade between states by one-third. In addition, the findings indicate that the effects of civil wars on trade are not limited to countries where the civil wars are occurring but also affect joiners. Furthermore, the outcome types of civil wars have repercussions for future bilateral trade and, under certain situations, their effects can be alleviated.

Signorino and Ritter developed and advocated a new measure of the political similarity of states ( S). They demonstrated logical flaws associated with the common Kendall's τ b-based alliance similarity measure and showed that using S may yield quite different similarity estimates. But without a broader empirical comparison and analysis using S, the full empirical ramifications of this difference is not known. In this study, a comparison of S versus τ b is conducted over a wide spatial and temporal domain, examining the relationship between S, τ b, expected utility scores, and conflict. Despite significant positive correlations, important differences in the distribution of S and τ b-based measures of alliance similarity are found. It should not be assumed that the measures are substitutable. Reanalysis of an important expected utility theory of war shows a stronger relationship between equilibrium predictions and conflict when S is used versus τ b.