Not All’s Fair in Love and War

Some composite states, notably Poland-Lithuania and the Holy Roman Empire, outlived the Peace of Westphalia by over one hundred years. This is puzzling for the study of international politics because good theoretical reasons expect the multiple countervailing pressures acting on these states to have brought about a rapid decline and dissolution. In this dissertation, I propose a theoretical approach that satisfactorily accounts for why some composite states survived until the dawn of the Napoleonic Wars. The theory of dynasticism and dynastic deterrence argues that dynastic intermarriage and proximate kinship ties between dynastic rulers created deterrent effects that led to stability on the level of sovereign control. The most direct consequence of this theory is that hereditary monarchs with dynastic aims will tend to avoid waging wars of absolute conquest against each other, though wars of limited gains are not precluded. Given the inability of competing explanations—a reconstructed early modern realism and intergenerational leadership learning—to account for both the manner of survival and demise of composite states that lived till old age, it can be strongly inferred that dynastic deterrent effects ensured longevity by protecting such polities from facing conquest-attempts from other monarchs, the most serious existential threat these composite states could have faced. The reason that dynastic deterrence holds is because dynastic wives and families of origin play the role of hostages. The parental house of the dynastic wife will tend to avoid wars of conquest against the kingdoms wherein reside their daughters, and similarly dynastic husbands will avoid conquering the birth-dynasty of their wives. In addition, wars of conquest damage the reputation of the dynastic house of a monarch, and this in turn harms the marriage chances of dynastic heirs. Wars of conquest, then, act at cross-purposes with the ubiquitous motive of dynastic aggrandizement, which aims to uplift the power and prestige of the dynastic house, and were largely disdained (with some exceptions) by the rulers of ancien régime Europe. It should be noted that this dynamic did not hold in the colonies, but I do not attempt in this dissertation to answer the question of why. In the empirical case analyses, I use this theoretical framework to explain the early dissolution of two composite states (England-Scotland and the Iberian Union) when juxtaposed with other composite states that survived for longer in their same regions, and the longevity and eventual demise of two further composite states (Poland-Lithuania and the Holy Roman Empire) after weathering some near-death crises. Oft mentioned but rarely studied directly, dynasticism and dynastic intermarriage have been largely ignored by the field of International Relations. This is unfortunate, as the ties of marriage and kinship between early modern dynastic rulers represent a fertile source of theoretical insights and empirical material for testing contemporary theories and deriving puzzles. I hope this study will stimulate further research into this fascinating area.