The surprising reason is that political instability has produced a hike in oil prices which has also encouraged (along with cheap money and abundant liquidity) an even bigger rise in the prices of many commodities such as copper, nickel, tin and iron ore. With the more liberalized global market (due to what we call "globalization") helping keep inflationary pressures in check, the benefits of growth have been spread out more widely, generating 5% annual GDP growth in sub-Saharan Africa, for example, and national growth rates ranging from 3-15% in Latin America and the Middle East.

It may not last: Oil prices have fallen 35% in six months, confounding almost all the forecasts, and commodities have slid too. But so far the process has been beneficial.

This growth has been stabilizing in political terms because it has brought a boom to the Arab Gulf, which felt sore about the U.S. invasion of Iraq, and has added hugely to government revenues in countries like Saudi Arabia, helping them buy off dissent and stave off worries about youth unemployment. Yes, dear oil has also helped encourage Iran and Venezuela to behave provocatively. But so far that has destabilized newspaper headlines far more than whole countries or regions.

Meanwhile, we may feel that politically the world is a mess, but our feelings don't entirely fit the facts -- at least the immediate facts. There are fewer inter-state wars now than there were five, ten or fifteen years ago. The conflicts we are most disturbed about -- Iraq, Israel, Sri Lanka -- are civil wars. The country whose prestige has been damaged most by the debacle in Iraq is of course the United States, so we tend to think of this as politically highly significant. And it may prove to be, but it isn't right now.

The big reason why the world economy is unaffected by turmoil in the Middle East, or even by the nuclear weapons programs of Iran and North Korea, is that the world's great powers -- America, China, Russia, the EU countries, India and Japan -- are more or less friendly with one another and more or less co-operative with one another. None is seeking to stoke up conflict with any of the others.

When might political messes produce economic messes too? It would happen when the great powers start to tussle, putting deep doubts in the minds of traders and investors, or when a lesser power executes cross-border aggression carrying truly global consequences, such as setting off a nuclear bomb.