Discerning the Causal Relationships Between Great Powers' Membership in Intergovernmental Organizations and Their Initiation of Militarized Disputes

Recent research suggests that intergovernmental organizations (IGOs) contribute to peace. The relevant evidence is based on shared IGO memberships by two states which manage to stay in peace. This article seeks to determine whether, in and of itself, the number of IGOs to which a state belongs is a predictor of its propensity to initiate militarized disputes (that is, whether the causal inference based on dyadic data is sustained when one turns to monadic evidence). Moreover, it seeks to discern any selection bias to the extent that peaceful states may be predisposed to join IGOs, so that both their membership in IGOs and their peaceful foreign relations are due to this same predisposition (implying that participation in IGOs does not make an independent and separate contribution to this state's peacefulness). This article also takes up the endogeneity question, which asks whether membership in IGOs may itself be encouraged by a prior history of peaceful relations. A number of hypotheses regarding the relationship between IGO membership and initiation of militarized disputes are analyzed for the historical data series of eight states which have been great powers at one time or another. Autoregression results show that the predominant causal flow goes from these states' membership in intergovernmental organizations to their incidence of initiating militarized disputes, with the former having a positive impact on the latter. There are, however, some instances when the causal arrow is reversed and when a negative effect between the two variables is indicated. In these latter instances, less conflictual foreign relations have apparently encouraged greater involvement in intergovernmental organizations at a subsequent time. Contrary to our expectation, after controlling for autocorrelation in the time series, the number of IGO memberships for the states studied in this article has not, with the seeming partial exception of Italy, tended to discourage their proclivity to initiate militarized disputes.