Treb Allen - Dartmouth

How does the interplay of geography and political-economic forces affect the shape of nations? This paper presents a quantitative framework for characterizing the equilibrium evolution of national boundaries in a world with a rich geography. The framework delivers simple equilibrium conditions based on the efficient transportation of resources that arise from multiple disparate political economic micro-foundations. I characterize the existence, uniqueness, and efficiency of the equilibrium and provide a simple algorithm for its calculation. When combined with detailed spatial geography data from Europe, the equilibrium conditions well approximate observed borders, and the framework is able to successfully predict the evolution of national boundaries and resulting conflict across Europe over the past millennia. Finally, I apply the framework to ask how the changing spatial distribution of resources arising from climate change may alter European borders in the future, finding that the Crimean Peninsula and surrounding area are especially susceptible.