Ruler Autonomy and War in Early Modern Western Europe

Following Kant, many scholars have argued that rulers often benefit more from war than do their subjects, and thus that rulers with more autonomy from subjects will initiate more wars. They usually test this argument by focusing on whether democratic states are less prone to initiate wars than autocracies, and generally find little or no relationship. These are not adequate tests of the general argument, since they turn both ruler autonomy and the interests of actors into rough dichotomies (democracy vs. autocracy, rulers' interests vs. interests of all subjects), and they ignore opportunity costs. This article uses a model of state policy formation based on agency theory to provide a better measure of ruler autonomy by differentiating between institutional autonomy and resource autonomy. We also use a more nuanced specification of the interests of different groups of subjects, taking their opportunity costs into account. This model allows us to derive more precise propositions about the relationship between ruler autonomy and war initiation. An analysis of war in four Western European states (England, France, Sweden, and Spain) between 1400 and 1700, using logit regression and qualitative comparative analysis, provides some support for the central propositions of the theory.