Editor's note: Robert Kagan is a senior fellow in Foreign Policy at Brookings. His most recent book is "The World America Made." He is the featured speaker at "Election 2012: The Global Challenge for the Next President," which will be streamed live at CNN OpinionThursday, March 15 at 1 p.m. ET.
By Robert Kagan - Special to CNN
We take a lot for granted about the way the world looks today - the widespread freedom, the unprecedented global prosperity (even despite the current economic crisis), and the absence of war among great powers.
In 1941 there were only a dozen democracies in the world. Today there are more than 100. For four centuries prior to 1950, global GDP rose by less than 1 percent a year. Since 1950 it has risen by an average of 4 percent a year, and billions of people have been lifted out of poverty.
The first half of the 20th century saw the two most destructive wars in the history of mankind, and in prior centuries war among great powers was almost constant. But for the past 60 years no great powers have gone to war.
This is the world America made when it assumed global leadership after World War II. Would this world order survive if America declined as a great power? Some American intellectuals insist that a "Post-American" world need not look very different from the American world and that all we need to do is "manage" American decline. But that is wishful thinking. If the balance of power shifts in the direction of other powers, the world order will inevitably change to suit their interests and preferences.
Take the issue of democracy. For several decades, the balance of power in the world has favored democratic governments. In a genuinely post-American world, the balance would shift toward the great power autocracies. Both China and Russia already protect dictators like Syria's Bashar al-Assad. If they gain greater relative influence in the future, we will see fewer democratic transitions and more autocrats hanging on to power.
What about the free market, free trade economic order? People assume China and other rising powers that have benefited so much from the present system would have a stake in preserving it. They wouldn't kill the goose that lays the golden eggs. But China's form of capitalism is heavily dominated by the state, with the ultimate goal being preservation of the ruling party.