geopolitics, analysis of the geographic influences on power relationships in international relations. The word geopolitics was originally coined by the Swedish political scientist Rudolf Kjellén about the turn of the 20th century, and its use spread throughout Europe in the period between World Wars I and II (1918–39) and came into worldwide use during the latter. In contemporary discourse, geopolitics has been widely employed as a loose synonym for international politics.

Arguments about the political effects of geography—particularly climate, topography, arable land, and access to the sea—have appeared in Western political thought since at least the ancient Greek era and were prominent in the writings of philosophers as diverse as Aristotle (384–322 bc) and Montesquieu (1689–1745). The best-known body of geopolitical writings is the extensive literature of the late 19th and early 20th centuries, much of which focused on the impact on world politics of the new technologies of the Industrial Revolution. Alfred Thayer Mahan, Halford Mackinder, John Seeley, Karl Haushofer, Friedrich Ratzel, H.G. Wells, Nicholas Spykman, Homer Lea, Frederick Teggart, Frederick Jackson Turner, James Burnham, E.H. Carr, Paul Vidal de la Blache, and others applied materialist approaches to contemporary problems. These and other writers tended to mix analysis with policy advocacy, and some exhibited many of the most pernicious racial and class prejudices of the era.

Geopoliticians sought to understand how the new industrial capabilities of transportation, communication, and destruction—most notably railroads, steamships, airplanes, telegraphy, and explosives—interacting with the largest-scale geographic features of the Earth would shape the character, number, and location of viable security units in the emerging global international system. Most believed that the new era of world politics would be characterized by the closure of the frontier, territorial units of increased size, and intense interstate competition; most also thought that a great upheaval was imminent, that the balance-of-power system that helped to maintain order in Europe during most of the 19th century was obsolete, that the British Empire (the superpower of the 19th century) was ill-suited to the new material environment and would probably be dismembered, and that the United States and Russia were the two states best situated in size and location to survive in the new era. Geopoliticians vigorously disagreed, however, about the character, number, and location of the entities that would prove most viable.

Mahan’s historical analysis of the rise of the British Empire was the starting point for the geopolitical debate. Arguing that the control of sea routes was decisive because of the superior mobility of the oceanic sailing vessel over animal-powered land transport, Mahan claimed that there was a tendency for maritime trade and colonial possessions to be controlled by one well-positioned maritime state.With the advent of the railroad, Mackinder posited that land power would trump sea power. Through his “heartland” theory, which focused on the vast interior regions of Eurasia made accessible by railroads, Mackinder argued that any state that was able to control the heartland would control world politics and thus pose the threat of a worldwide empire. In contrast, Spykman argued that the “rimland” region of Eurasia, which stretches in a crescent from Europe to East Asia, had a tendency to unite in the hands of one state and that the country that controlled it would likely dominate the world. Alternatively, Haushofer and other German geopoliticians who supported German international dominance developed the theory of the “pan-region,” a continent-sized block encompassing an industrial metropol (or major power) and a resource periphery, and posited that four regions—pan-Europe (which included Africa) dominated by Germany, pan-Asia by Japan, pan-America by the United States, and pan-Russia by the Soviet Union—were likely to emerge as an intermediate stage before global German dominance. The emergence of the airplane led some geopoliticians (e.g., Giulio Douhet) to downplay the role of both naval and land power in favour of air superiority. During World War II some even predicted that technological developments would render naval power obsolete.

The popularity of geopolitical theory declined after World War II, both because of its association with Nazi German and imperial Japanese aggression and because the emergence of nuclear explosives and ballistic missiles reduced the significance of geographical factors in the global strategic balance of power. However, geopolitics continued to influence international politics, serving as the basis for the United States’ Cold War strategy of containment, which was developed by George Kennan as a geopolitical strategy to limit the expansion of the Soviet Union. Political geographers also began to expand geopolitics to include economic as well as military factors.