The Liberal Peace: Interdependence, Democracy, and International Conflict, 1950-85

TLDR

Classical liberals argued that democracy and free trade reduce war. The study tests the democratic peace hypothesis by adding a measure of economic interdependence to previous analyses. The authors use logistic regression on 1950‑85 dyads, controlling for growth, alliances, contiguity, and power, to assess regime type and interdependence effects. Results show that trade strongly promotes peace, especially among war‑prone contiguous states, and that economic interdependence, constrained executives, and non‑violent norms reduce conflict.

Abstract

The classical liberals believed that democracy and free trade would reduce the incidence of war. Here we conduct new tests of the `democratic peace', incorporating into the analyses of Maoz & Russett (1993) a measure of economic interdependence based on the economic importance of bilateral trade. This allows us to conduct a simultaneous evaluation of the effects of regime type and interdependence on the likelihood that a pair of states will become involved in a militarized interstate dispute. We control in all our analyses for a number of potentially confounding influences: growth rates in per capita income, alliances, geographic contiguity, and relative power. Our logistic regression analyses of politically relevant dyads (1950-85) indicate that the benefits of the liberals' economic program have not been sufficiently appreciated. Trade is a powerful influence for peace, especially among the war-prone, contiguous pairs of states. Moreover, Kant (1991 [1795]) was right: International conflict is less likely when external economic relations are important, executives are constrained, and societies are governed by non-violent norms of conflict resolution.