Proximate Threats and the Motivation to Intervene in Civil War

• In Event: Civil War Dynamics

Abstract

Intervention in a civil war is a costly behavior. States who pursue such a course face heavy economic and political implications. Despite the costs, however, 68% of civil wars from 1975-2009 have involved at least one external actor. If intervention is costly, why is it so common? Previous work on the causes of intervention have focused primarily on the influence of security concerns—the threat the conflict poses to third-parties. Despite the broad use of threat as a theoretical construct in the intervention literature, efforts to measure the threat that a civil war poses on external states have been lacking. Previous research primarily uses conflict intensity, operationalized as battle deaths, as a measure of threat, but there is a disconnect between this measure and primary threat mechanisms in the literature, which are focused mainly on spillover effects. Third parties are likely to interpret the threat of spillover as a function of both intensity and proximity. Using newly coded geospatial data from ACLED and PRIO-GRID, we develop measures of several types of threats that civil wars can pose on external states that take into account the likelihood of spillovers via geography. We use these measures to test theories of conflict intervention. We find that states are significantly more likely to intervene based on threats to their national security, primarily from the possibility of conflict spilling over their border, rather than simple intensity of the neighboring conflict. These spillover effects are also demonstrated to have more explanatory power than economic variables.

Authors

• Megan Becker, University of Southern California

• Jacob Tucker, Princeton University