Secession and the invisible hand of the international system

This article argues that 1945 constitutes an historical inflection point from a period of state expansion to state contraction and that this transformation is primarily the result of changes at the international level. Just as security and economic pressures drove lead states to expand in earlier times, changing conditions in the post-1945 period led to a contraction in state size. The change from multipolarity, the development of the territorial integrity norm, the shift to nuclear deterrence, and the burgeoning global economy contributed to the milieu in which states evaluate the costs and benefits of holding territory, and this has enabled states to permit secession more frequently. The result has been an increase in the rate of peaceful secession and a corresponding proliferation in the number of sovereign states. I test this argument both qualitatively and quantitatively using original data on secessionist movements and internal administrative regions between 1816 and 2005.