If you want to know what Russia, China or Iran will do next, don't read their newspapers or ask what our spies have dug up—consult a map. Geography can reveal as much about a government's aims as its secret councils. More than ideology or domestic politics, what fundamentally defines a state is its place on the globe. Maps capture the key facts of history, culture and natural resources. With upheaval in the Middle East and a tumultuous political transition in China, look to geography to make sense of it all.

As a way of explaining world politics, geography has supposedly been eclipsed by economics, globalization and electronic communications. It has a decidedly musty aura, like a one-room schoolhouse. Indeed, those who think of foreign policy as an opportunity to transform the world for the better tend to equate any consideration of geography with fatalism, a failure of imagination.

But this is nonsense. Elite molders of public opinion may be able to dash across oceans and continents in hours, allowing them to talk glibly of the "flat" world below. But while cyberspace and financial markets know no boundaries, the Carpathian Mountains still separate Central Europe from the Balkans, helping to create two vastly different patterns of development, and the Himalayas still stand between India and China, a towering reminder of two vastly different civilizations.

Technology has collapsed distance, but it has hardly negated geography. Rather, it has increased the preciousness of disputed territory. As the Yale scholar Paul Bracken observes, the "finite size of the earth" is now itself a force for instability: The Eurasian land mass has become a string of overlapping missile ranges, with crowds in megacities inflamed by mass media about patches of ground in Palestine and Kashmir. Counterintuitive though it may seem, the way to grasp what is happening in this world of instantaneous news is to rediscover something basic: the spatial representation of humanity's divisions, possibilities and—most important—constraints. The map leads us to the right sorts of questions.

Why, for example, are headlines screaming about the islands of the South China Sea? As the Pacific antechamber to the Indian Ocean, this sea connects the energy-rich Middle East and the emerging middle-class fleshpots of East Asia. It is also thought to contain significant stores of hydrocarbons. China thinks of the South China Sea much as the U.S. thinks of the Caribbean: as a blue-water extension of its mainland. Vietnam and the Philippines also abut this crucial body of water, which is why we are seeing maritime brinkmanship on all sides. It is a battle not of ideas but of physical space. The same can be said of the continuing dispute between Japan and Russia over the South Kuril Islands.