Polarity

Some theorists suggest that the number of “great powers” or “poles” at any given time determines the stability and peacefulness of the “international system.” A non-polar system is logically possible but historically rare.

The Pax Romana is the classic example of a unipolar world. It is of particular interest because the immediate post-Cold War period also is unipolar, the United States being the only current power with global reach. Rome became an empire more by accident than design. A common language, a law code that is one of the great intellectual achievements of mankind, and unsurpassed engineering skills translated into a system of roads, aqueducts, and fortifications that combined to keep the peace within the Roman Empire. The elite enjoyed a common high culture. A highly trained professional army kept the peace—but was almost continually at war to do so. These were small wars fought by hardened professionals on the fringes of the empire, hardly noticed by the majority of the citizens. They were like the wars the British army fought in Asia and Africa during the nineteenth century, or those that the American army fought in Central America and the Caribbean in the twentieth and in the Middle East in the late twentieth and early twenty-first centuries.

The era of peace begun by Augustus collapsed with Marcus Aurelius. Caligula exposed the flaw in the system: the emperors were above the law. Claudius, Trajan, and Hadrian resumed expansion of the empire, requiring an army that was beyond the ability of the Roman economy to sustain. Despite Roman engineering skills, industry remained primitive. Slavery kept wages low for freemen and high taxes drove free peasants off their lands and into the cities where there was no work. Commerce withered, cities decayed, and civil unrest grew. Formidable barbarian armies appeared along the Rhine and the Danube. Many have asked if current efforts to extend the Pax Americana to the Middle East will prove a similar over-reach with similar results. Others ask if there is any alternative if a modicum of peace and prosperity is to be had on a global scale.

In theory, bi-polar systems exhibit intense rivalry. Each power will try to draw neutrals to itself, seek defections from the other camp, and try to prevent defections from its own. Each will intervene on opposite sides in wars and crises, particularly in states that have important resources or are strategically located. Historical examples of bi-polar systems include Achaemenid-Greek (later Macedonian), Roman-Carthaginian, Byzantine-Sassanian, Ottoman-Byzantine, and US-USSR. Wars were frequent in all five periods, including wars between the two major powers of the day with the exception of the last (1947-1989). Nearly 300 wars and 250 crises began during the Cold War—an astounding average of one a month for 42 years. They took the same 50,000,000 lives as World War II itself. Unlike earlier bi-polar systems, the US and USSR never went to war with one another although they came close at least twice. This usually is attributed to nuclear weapons, which gave the US and the USSR the ability to destroy not just one another but the world.

This was the doctrine of Mutually Assured Destruction [MAD], which many credit for the Cold War remaining cold.

Finally, some theorists argue that multi-polar systems are prone to war because there are so many ways to miscalculate and so many ways to become un-balanced. Other theorists reply that the difficulty of judging strength makes states less willing to risk war. Alliances change constantly in multi-polar systems in efforts to maintain the balance of power and minimize the number and severity of wars. A third group of theorists maintains that multi-power periods end with the rise of a new great power from the small wars that characterize them (Figure 12.1). No multi-polar systems were peaceful, although just how many wars there were for some of the earlier periods is not always clear.

All this is of more than academic interest because many see the early twenty-first century decline of the US leading to a new multi-polar and thus unstable system, with China, India, and the US as global powers and Brazil, Germany, Iran, Russia, South Africa, and Turkey as regional ones.

Optimists such as Ikenberry (2011) believe that the current international system characterized by widespread if not universal freedom, prosperity, and peace will not only survive, but thrive. The pessimists respond that the decline of the US will shift the balance of power to autocracies. Beyond its already substantial land and air forces, China is developing space war capabilities, aggressively hacking foreign computer systems, building a blue-water navy, developing anti-ship missiles and undersea sensors, and making basing arrangements with countries such as Myanmar and Pakistan.

Making allowance for differences in historical circumstances and the complications posed by alliances, polarity does not seem a particularly useful concept in understanding the cause of war, or for developing policies that might reduce its occurrence. War was common under all four possible types of polarity and there is no clear pattern to the terminal “event.”