Civil War Diffusion and Regional Motivations for Intervention

Third-party states consider the regional destabilization consequences of civil wars when deciding to intervene. However, previous work implicitly assumes that potential interveners base their intervention decisions solely on their links to the civil war country. This approach is unlikely to reflect the regional concerns of interested parties. When a civil war is increasingly likely to infect its surrounding region, potential interveners with strong interests in those states neighboring the conflict will be more likely to intervene to contain the violence. Thus, relationships outside the civil war state—intervener dyad are causally associated with intervention. To test these arguments, the author accounts for the contagious properties of civil wars and the regional interests of third parties, constructing dynamic measures to represent the contagion threat posed to third party regional interests. Analyses of these measures support the argument that third parties are increasingly likely to intervene as the risk of diffusion increasingly threatens their regional interests.