This essay extends a cooperative game-theoretic model of balance of power in anarchic
international systems to include considerations of the asymmetry which geography
occasions in the offensive and defensive capabilities of countries. The two
substantive ideas which concern us are a formalization of the notion of a "balancer"
and that of a "central power." What we show is that in stable systems, only specific
countries (such as Britain in the 18th and the 19th centuries) can play the role of
balancer, and that the strategic imperatives of a central country (e.g., Germany in
the period 1871-1945) differ in important ways from those of "peripheral" countries
