Prior Commitments: Compatible Interests versus Capabilities in Alliance Behavior

The trade-off model of alliances offers a theory of alliance formation & duration that has significantly advanced our understanding of why states enter into alliances & why these alliances persist. However, we argue that extant tests of this model are improperly specified, greatly reducing the overall usefulness of the trade-off theory, & we therefore use this paper to bring foreign policy interests back into the model. Specifically, we argue that dyadic interest similarity best captures the motivations behind alliance formation & termination, & together with capability concentration, accurately predicts when dyads will seek alliances & what types of alliances are likely to be formed. We test our theory using a greatly expanded temporal domain (1648-2000), & our results are consistent & robust across each model. 4 Tables, 2 Figures, 21 References. Adapted from the source document.