Economic Development and Warlikeness

Thinkers have offered four theories for the impact of a state’s rising economic development (or riches) on its international warlikeness or proclivity to fight any other state over a dispute. As a state develops it becomes: less warlike; more warlike; first more and then less warlike; or it keeps its warlikeness throughout. Most empirical studies treated riches as a control variable. Extant results painted a mixed picture. We outline prior theoretical and empirical works, mathematically model warlikeness as a choice, operationalize the model for empirical work, and estimate its parameters in a large sample of states and years from 1870 to 2010. We find rising riches made states more warlike on average, ceteris paribus. The marginal effect of riches rose with factors such as power, trade, population, and democracy, ceteris paribus. We apply the results to evaluate possibilities in the coming decades should riches grow for given control variables’ scenarios, assuming history can tell us something of value about the future.