Big or little, President Obama will have his war. President Bush had his, the Iraqi War and the War on Terror, the latter being a rather different business from the conventional war between states. Most US presidents have had to fight, and several of the handful of great ones were made so on the field of battle.

Some wars, and some single battles, have changed the course of human history. Just focusing on Western history, which has dominated the world for over 2,000 years, the defeat of the Persians at Arbela in 331 BC by Alexander the Great destroyed one empire and launched another, which led to the Hellenization of the world with Greek culture to this day. The battle of Jerusalem in 70 AD, which led to the destruction of the city by the Romans and the global dispersion of the Jews, including Jewish Christians, radically altered the flow of world history, certainly as far as religion is concerned.

The fall of Rome to so-called barbarian forces in 476 AD, which gave rise to the succeeding nations and empires of Europe, is another case. Among many other possibilities, the defeat of the Spanish Armada by vastly inferior English forces in 1588 has to qualify. That naval victory created space for the emergence of a Protestant English empire, which at its peak, covered a quarter of the globe.

The success of the American rebels against the forces of the greatest empire of the time in 1776, led to the creation of the United States of America, which now stands astride the world like an unparalleled colossus.

World-changing consequences

But it is the world-changing consequences of those two mega-conflicts of the last century, called World War I and World War II, that we want to focus on. Following the hot World War II was the Cold War, with its own massive global consequences still outflowing. And now there is that peculiar War on Terror, which must significantly affect world history.

Barack Obama is coming to the presidency of the world's sole superpower, which is a product of these and other conflicts.

Millions of people died in World War I, which redefined war from an engagement of armies to the total mobilisation of entire populations, the massive appropriation of resources by the State, and the use of specially developed scientific technologies for total conflict. The war began with cavalry regiments riding forth, but ended with aircraft flying high.

Winston Churchill noted shortly after the conflict ended, as secretary of state for war: "All the horrors of all the ages were brought together, and not only armies but whole populations were thrust into the midst of them. Neither peoples nor rulers drew the line at any deed which they thought could help them to win. Every outrage against humanity or international law was repaid by reprisals - often of a greater scale and of longer duration." Churchill clinically spelled out the outrages, then concluded, "When all was over, torture and cannibalism were the only two expedients that the civilised, scientific, Christian states had been able to deny themselves: and they were of doubtful utility."

But beyond the atrocities, British historian and journalist, Paul Johnson, points out in A History of the Modern World that, "the effect of the Great War was enormously to increase the size, and therefore the destructive capacity and propensity to oppress, of the state. The war demonstrated both the impressive speed with which the modern state could expand itself and the inexhaustible appetite which it thereupon developed both for the destruction of its enemies and for the exercise of despotic power over its own citizens".

More destructive war

World War II was even more destructive of human life and property and more favourable to the relentless growth of the State. Even before the conflict ended, the leaders of the Great Allied Powers were meeting to hammer out the architecture of a new world order safe for peace. The natural tensions between democratic, capitalist partners, on the one hand, and the communist Soviet Union on the other, inevitably led to the Cold War, which, thankfully, did not erupt into World War III in a world armed with nuclear weapons and more killing power than humankind has ever known.

Among the institutions created were the United Nations and the (in)famous Bretton-Woods pair, the International Monetary Fund (IMF) and the World Bank. In each of them America dominated. The American dollar was made the standard currency in the operations of the IMF and the World Bank and thus became the benchmark currency of the world. Subsequent history has clearly indicated that when it really maters, the UN does not really matter.

This World War II world is unravelling. The global-financial- crisis-turned-economic-crisis is severely challenging the Bretton-Woods arrangement. The strengthening euro is challenging the US dollar as the currency of choice to run the global economy. On top of all this, terrorism has risen as a new global threat, the global environment is under severe threat from human action, and there is an emergent energy crisis.

It is this world that Barack Obama leads from the United States White House. And there is no question about who is emperor. It was not the United Nations, the IMF, or the World Bank which called the G20 meeting last week-end to attempt to reconstruct the shattered 'financial architecture' of the global economy. It was the US President Bush. And in an unprecedented move, the president-elect was invited but declined. President Obama will chair the next session.

Expanding American power

The crises of the times will expand American power as its participation in WWI and WWII did. Its key competitor/ally will be the European Union, entrenching a North Atlantic axis of power on a scale that the world has never seen. Sure, in the spirit of democracy and multilateralism, others will be at the table. The G7 is growing, and a G20 met last week. But they cannot not know that they are only playing second fiddle.

What President Barack Obama and his immediate successors will do with the unrivalled power of the United States in a one-power world is the central geopolitical question of our times. How he wages war and conducts the peace between wars will provide a most powerful insight.

Martin Henry is communications consultant. Feedback may be sent to medhen@gmail.com or columns@gleanerjm.com.