The global power structure has a profound impact on how foreign policies are conducted by leaders, especially the major powers and superpowers. Operational codes for various global power distributions, as reformulated from principles developed by political scientist Morton Kaplan, focus on how countries must orient their military policies in the very differing historical eras of unipolarity, bipolarity, and multipolarity. Most discussions are reports on actual historical periods, but some are Kaplan’s hypothetical power distributions.