This article examines the effect of interstate signals on the probability of civil war onset. Using a bargaining framework, the author argues that costly signals should have no effect on the likelihood that a civil war begins because they allow the government and opposition to peacefully adjust their bargaining positions to avoid the costs of fighting. In contrast, cheap signals can disrupt intrastate negotiations, which makes conflict more likely by increasing the likelihood that one of the competing parties will make excessive demands. This argument is tested using measures for sanctions, troop mobilization, alliances, and trade ties as indicators for costly signals, as well as events data as measures for cheap signals. Results demonstrate that cheap signals strongly affect the probability of civil war onset, while costly signals do not. Cheap signals hostile to the government increase the likelihood of civil war onset, while cheap supportive signals have a pacifying effect
Thyne, Clayton L. (2006) Cheap Signals with Costly Consequences: The Effect of Interstate Relations on Civil War, Journal of Conflict Resolution 50 (6): 937–961.