From empire to nation-state: Explaining wars in the modern world, 1816-2001

TLDR: In this paper, the authors introduce a new data set that records the outbreak of war in fixed geographic territories from 1816 to 2001, independent of the political entity in control of a territory.

Abstract: The existing quantitative literature on war takes the independent nation-state as the self-evident unit of analysis and largely excludes other political types from consideration. In contrast, the authors argue that the change in the institutional form of states is itself a major cause for war. The rise of empires and the global spread of the nation-state are the most important institutional transformations in the modern age. To test this hypothesis, the authors introduce a new data set that records the outbreak of war in fixed geographic territories from 1816 to 2001, independent of the political entity in control of a territory. Analysis of this data set demonstrates that wars are much more likely during and because of these two transformations. For the transformation to the modern nation-state, the authors confirm this hypothesis further with logit regressions that control for variables that have been robustly significant in previous research. The results provide support for the main mechanisms that exp...