Extending Offensive Realism: The Louisiana Purchase and America's Rise to Regional Hegemony

John Mearsheimer suggests that, whenever possible, great powers are constrained to seek regional hegemony, the safest feasible situation for a state. This objective is hard to achieve because other great powers want to block the attempt, but it is doable because buck-passing and other hurdles make balancing inefficient. Contra Mearsheimer, I argue that it is the absence of balancers, not balancing inefficiencies, that best explains when states can hope to dominate their neighborhoods. Regional hegemony is only achievable when it is easy. I use property space techniques to develop an extended version of offensive realism that clarifies why states will sometimes prefer not to block a hegemonic bid. In particular, I argue that local considerations will often prevent a continental great power from responding to a rising state in another region. I test my argument by process tracing the U.S. purchase of Louisiana and show that France's decision to sell is best explained by its pursuit of its own territorial ambitions. My extended version of offensive realism suggests that its single success story of the last 200 years, U.S. dominance of North America, provides no encouragement to contemporary states contemplating a bid for regional hegemony.