Capitol Hill Blue Forums Political Issues Foreign Policy & News "Unintended Consequences of Military Intervention"

Nearly all wars are fought over control of territory, and sometimes over specific economic resources such as minerals, farmland, or cities. The patterns of victory and defeat in wars through history have shaped the direction of the world economy and its institutions. For example, when Portugal in the 16th century used ship-borne cannons to open sea routes to Asia and wrested the pepper trade away from Venice (which depended on land routes through the Middle East), it set in motion a profound shift in Europe's economic center of gravity away from the Mediterranean and towards the Atlantic.

Wars of conquest can more than pay for themselves, if successful. The nomadic horse-raiders of the Iron Age Eurasian steppes found profit in plunder. Similarly, the 17th- to 18th-century Dahomey Kingdom (present-day Benin) made war on its neighbors to capture slaves, whom it sold to Europeans at port (for guns to continue its wars). War benefitted the Dahomey Kingdom at the expense of its depopulated neighbors. Likewise, present-day armies in Democratic Congo and Sierra Leone are fighting to control diamond production areas, which in turn fund those armies. According to one controversial school of thought, states in undertaking wars behave as rational actors maximizing their net benefits. However, wars are fought for many reasons beyond conquering valuable commodities.

Successful empires have used war to centralize control of an economic zone, often pushing that zone in directions most useful to continued military strength. Transportation and information infrastructures reflect the central authority's political control. When European states conquered overseas colonies militarily (16th to 19th centuries), they developed those colonies economically to benefit the mother country. For example, most railroads in southwestern Africa were built - and still run - from mining and plantation areas to ports. Empires, however, inherently suffer the problems of centralized economies, such as inefficiency, low morale, and stagnation. Some scholars argue that empires also overstretch their resources by fighting expensive wars far from home, contributing to their own demise.

In recent centuries, the largest great-power wars have been won by ocean-going, trading nations whose economic style differs sharply from that of land-based empires. Rather than administer conquered territories, these "hegemons" allow nations to control their own economies and to trade fairly freely with each other. This free trade ultimately benefitted hegemons as advanced producers who sought worldwide export markets. The Netherlands after the Thirty Years' War (1648), Britain after the Napoleonic Wars (1815), and the United States after the World Wars (1945) each enjoyed predominance in world trade. By virtue of superior naval military power, each of these great powers shaped (and to some extent enforced) the rules and norms for the international economy. For example, the international financial institutions of the Bretton Woods system grew out of U.S. predominance after World War II. As nations recover in the decades following a great war, however, their power tends to equalize, so a hegemon's raw power gradually matters less, and international economic institutions tend to become more independent - surviving because they offer mutual benefits and help resolve collective goods dilemmas. For example, the United States today, despite its military predominance, does not unilaterally control the World Trade Organization.

Naval power has been used historically to win specific trading and extraction rights, in addition to its broader uses in establishing global economic orders. When asked the reasons for declaring war on the Dutch, a 17th-century English general replied, "What matters this or that reason? What we want is more of the trade the Dutch now have." U.S. warships in the 19th century forced open Japan's closed economy. And in the mid-1990s, both Canada and Russia used warships to drive away foreign fishing boats from areas of the high seas that shared fish populations with Canadian and Russian exclusive economic zones as defined under the UN Convention on the Law of the Sea. In recent decades, disputes over control of small islands - which now convey fishing and mining rights up to 200 miles in all directions, have led to military hostilities in the South China Sea and the Falklands/Malvinas, among others.

Military power has provided the basis for extracting tolls and tariffs on trade, in addition to its more direct role in conquest of resources and trade routes. Danish cannons overlooking the Baltic Sound gave the Danes for centuries a stream of income from tolls on the Baltic trade. River-borne trade in Europe faced similar choke-points where strategic military fortifications allowed tolls to be charged. The military defeat of the Ottoman empire, by contrast, cost Turkey the ability to control or tax traffic from the Black Sea to the Mediterranean, which today includes a large and growing number of oil tankers.