Alliances and Civil War Intervention

Abstract Governments have a number of structural advantages over rebel groups in civil wars, one of which is their greater ability to make credible international commitments. Governments can use foreign policy commitments to incentivize other states to provide them military support or deny support to their rebel groups. We analyze international intervention in civil conflicts between 1975 and 2017 and find that some kinds of alliances are associated with pro-government intervention, but all alliances are not equal. Alliances with consultation commitments are associated with interventions that provide materiel, training, intelligence, and/or other forms of non-troop support, while defense pacts are associated with both troop and non-troop support. Members of nonaggression and neutrality pacts are not more likely to intervene to support the government but are less likely to provide support to anti-government forces. We argue that alliances are not simply proxies for common interests; they sometimes involve specific bargains designed to aid a government in defeating rebels. Our evidence suggests that these agreements are successful at incentivizing the intended behavior. Governments use international security policy to protect the status quo domestically as well as internationally, and this affects our understanding both of civil wars and of alliance politics.