1
Conquest versus Commerce: Institutional Incentives for Formal Imperialism
Leo Blanken
Department of Political Science
The University of California, Davis
## email not listed ##
Scott Sigmund Gartner
Department of Political Science
The University of California, Davis
## email not listed ##
Presented at the Annual Meeting of the American Political Science Association
Washington DC, September 2005
Abstract: Formal imperial expansion is a phenomenon that is poorly explained by existing
international relations and political economy literature. We present a model of revenue
maximizing sovereigns choosing to conquer or not conquer regions based on their institutional
constraints and incentives, the institutional constraints and incentives of imperial rivals, as well
as the presence or absence of an “assurance framework” of institutions in the target region.
Selectorate dynamics drive institutional constraints. We find that small W states have a weakly
dominant strategy to always take because they are unable to obtain useful benefits without direct
imperial control. The small W (such as 19
th
century Portugal) state cannot politically sustain
free trade in its own domain, and cannot even benefit from other large W states providing free
trade zones. For large W states (such as 19
th
century Great Britain), when the belief in
attractive institutional target attributes is high, leaving is more likely to occur as a policy for a
large W type actor. Conversely, when the belief about an assurance framework is low, taking
becomes more attractive. For small W states, competition with other potential imperial states
has no effect. Large W states can free ride and benefit on a potential adversary’s free trade, but
fight to conquer areas that lack assurance frameworks. The model is formalized as games of
incomplete information, solved for by Bayes Nash equilibria. Employing primary and secondary
sources, we use the theory to explain European imperial expansion in nineteenth- century
tropical Africa – in particular, the carving up of African territory among the great powers
during the Berlin Conference of 1884-85.