Nearly as important as geography is the human factor. A nation must feed its people and protect its treasures, and sometimes, through necessity or greed, a country will be tempted to venture across borders into its neighbors’ backyards, searching for more reserves of wealth. Even if a country resists this temptation, it must nonetheless guard against other nations who may, for whatever reason, launch an attack.

These incursions are a given in international relations. Beyond that, what matters is the quality of play, in the manner of a chess game. Each side must see to its own best interests; its geographical and economic situations will set limits; and leaders must choose the best option among those available. In this respect, leaders tend to behave rationally, much like businesses or consumers who review the available marketplace choices before making a purchase.

The results, of course, can be bloody, but this doesn’t change the need for strategic thinking. After reporting from 40 countries, the author describes the decisions made by local governments in a way that suggests that they do, indeed, try to advance their countries’ interests by playing as good a game as they can.