The English School tradition offers a compelling framework for understanding war as an institution within an international society constructed by states. Nonetheless, analyses of the causes of inter-state insecurity offered by English School scholars are underspecified and fail to develop distinct middle-range theories based on these core insights. These problems can be remedied through an engagement with the subfield of quantitative conflict studies. This pairing of ‘scientific’ and ‘classical’ research traditions seems improbable, but the methodological barriers to conversation can be overcome if claims about the circumstances and causes of war are contextualised historically. Important findings in conflict research vindicate the English ...