Alliances and Civil War Intervention.

The article examines how different types of military alliance commitments influence international intervention in civil wars from 1975 to 2017. It finds that governments use alliances not only to deter external threats but also to secure support against internal rebel groups by making credible foreign policy bargains that rebel groups cannot easily replicate. Specifically, alliances with consultation commitments are linked to increased non-troop support (e.g., materiel, training, intelligence) for governments, while defense pacts correlate with both troop and non-troop pro-government interventions. Conversely, neutrality and nonaggression pacts do not increase pro-government intervention but are associated with a reduced likelihood of anti-government intervention, particularly visible troop support to rebels. These findings suggest that military alliances serve as strategic tools for incumbent governments to maintain domestic control by shaping the incentives of potential external interveners.