Testing Allies Through Conflict: Loyalty, Adverse Selection, and War

This article introduces a formal model showing how a powerful state, the patron, can ascertain the loyalty of a weaker ally, the client, by inducing a conflict between the client and a shared opponent. If the patron enjoins the client to adopt a more confrontational policy toward the opponent while only moderately preparing to intervene militarily, it will be able to differentiate a loyal client from a disloyal one. A loyal client will proceed to credibly signal its fidelity to the patron by proposing a confrontational policy that will provoke a conflict with the opponent, while a disloyal client will refrain from adopting such a policy. Knowledge of the client’s type enables the patron to subsequently dispense large-scale military and/or economic aid to a loyal client and eschew providing aid to a disloyal one, thereby reducing the cost of future abandonment by a disloyal client.