ABSTRACT Why do governments use interventions to shape the internal political composition of other states? Many explanations focus on intervention’s strategic utility, which can include a wider sphere of influence and enhanced state security. Alternatively, this article argues that how regimes view the internal political conditions of other states in relation to their own political spheres dictates the utility that they assign to intervention. Drawing on archival content related to Saudi Arabia’s intervention in the North Yemen Civil War (1962–1967), the article tests this political-threat explanation of intervention against the strategic-threat alternative.